This episode is of Sexplanations is sponsored by AdamandEve.com, an online store to buy sex toys for sex play. [WHIP CRACKING, COUGH].

Have you ever wondered why people have sex? For example fellatio (blowjobs).

There's no reproductive function. The first time it happened, the person with the penis had to have thought, “I'm putting my sensitive organ into a slobbery mouth with sharp teeth,” and then the person with the mouth had to have thought, “urine recently came out of that long fleshy stick I might choke on.” So why did they do it? And more interestingly to me, why do we keep doing it?

Behavioral psychologists believe that our behaviors, like receiving and performing oral sex, are shaped through reinforcement with reward or punishment. Reinforcement is a consequence of a behavior (usually positive) that increases the likelihood of that behavior in the future. And different types of reinforcement produce faster or slower results, or more regular and longer lasting results.

If oral sex is a reward for behaviors that your partner values, fixed ratio would be like a blowjob every 10th time you... fill in the blank: compliment your partner, clean the house.... Or one for one: every foot massage leads to nice relaxing mouth to genital play. On a graph, fixed ratio reinforcement looks like this: a slightly jagged, almost vertical line.

There's a lot of action in a short amount of time because the reward is based on the amount of behaviors, not on time. It doesn't matter if all ten compliments are given right now or over the next 10 weeks. It's that there were 10, or however many of those specific behaviors your partner is after.

As a result, sex lives operating on this reinforcement schedule tend to be fast paced. Here's another example of fixed ratio for masturbation: if every 100th stroke is orgasmic, it doesn't matter if you rub for minutes or hours. 100 is the number. So some people will speed through those strokes to get to the orgasm quickly.

And this can lead to what psychologists call extinction of a behavior, the gradual weakening or death of a response to a stimulus. While it's exciting at first to come and come and come and come, you might get burnt out. A variable ratio reinforcement schedule is much more resilient to extinction.

Again, it's about the amount of compliments or foot massages, not how much time has passed. But in this case, the amount isn't set - it varies. You might get oral after a shower, or oral after a shower and a nap and a meal, or oral after a meal and a nap.

You get the message that if you do a self-care task that's blowjob-worthy an average of two, you'll be rewarded with the blowjob. Noting, though, the average can be much higher than two. Variable ratio is the same reinforcement schedule that casino slot machines use.

People play for hours without a big win, pulling the handle again and again hoping that the next yank is going to be the one that delivers the jackpot! In sex, this might be masturbating for that one body-quaking orgasm. Let's say that you masturbated and got the oh so elusive orgasm but then tried again and couldn't, tried again and couldn't, 10 times over days, weeks without coming.

And then on the 11th try... [orgasm sound]. You'd try around 11 times in the future to masturbate with the same outcome, right? 8 times, 13, maybe 15 just knowing that it could be the one, then the next time you get there on the 10th. Variable ratio is very powerful and can pose a great challenge for some personality types.

For this reason, some sex lives are more oriented toward timed reinforcement. Fixed interval which would be like oral sex every two weeks or once a year. You do something that your partner wants to reinforce with [blowjob gesture] and after a fixed or certain amount of time, they're between your legs delivering.

This could be like witnessing you being an honest person, kind to the neighbor's cat, you paid the bills so on Sunday afternoon, so they hook you up with a humjob. Or you've never once pressured your partner to be sexual with you, so on your birthday you get a gherkin slurpin. Psychologists note that a problem with this type of reinforcement schedule is that people tend to wait until the last minute.

For example, a person may not do the dishes until Sunday night when they know it's blowjob time, so then the desired behavior tends to only happen when the deadline is looming. Variable interval is also a time-based reinforcement, but the time changes or varies. So you do something, like fulfilling one of your partner's fantasies, and at some time in the future, they treat you with oral attention (maybe even a fantasy version).

Kind of like a birthday blowjob, you know you'll get one once a year. But unlike a birthday blowjob, you don't know when during the year it will happen. As you might have imagined, fixed interval takes less effort to reinforce.

One kind gesture or 69 of them still means waiting a set amount of time for the treat. In comparison, variable interval or randomizing when the oral sex happens encourages incredible effort. You basically don't know when you're going to be recognized for your reinforceable behavior and so you're just awesome all the time.

Give me a blowjob, give me a blowjob, I'm being so gooooooood! B. F.

Skinner originally proposed these ideas about reinforcement. He tested them on rats with pellet dispensers. Press the lever, get the pellet -- variable, fixed, ratio, interval.

I think it's an incredibly helpful model to understand our sexualities. In relationships, it explains why some people incessantly ask for sex. They've been reinforced, probably unintentionally, that a variable ratio will illicit an eventual yes. (And if that's unwanted, switch to a fixed interval.) Kink culture uses fixed interval community gatherings called munches to create a comfortable way people can explore BDSM before playing.

They get together at a restaurant consistently every month, meet people, and it hopefully feels good to get acquainted and learn from others, reinforcing participation. It's natural to strive for certain outcomes, to want to modify our own behavior or another's to get a better response. It shouldn't be something we expect, though.

Psychology tells us that people are more likely to give blowjobs if the experience of giving them is reinforced. And people are more likely to earn blowjobs if those blowjobs are reinforcing. But this knowledge is to provide insight into our experiences, not to manipulate others.

Consent, creativity, and curiosity matter. Stay curious. Imagine being given this gift.

If you didn't know what it was, it might end up on a shelf as a silicone sculpture. It might. Touching it with my hands feels good and reinforces me to move it to other parts of my body.

People use stuffed animals, pillows, lotion bottles, vegetables, and electric toothbrushes to appease their genitals. Something like this or like this would certainly find their way to through positive reinforcement… and curiosity and creativity. The come hither mechanism on the head of this vibrator is fixed ratio.

I feel it. I like it. And I keep feeling it.

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