Hooking up is kind of like graphing logs. You plot the points of your intersecting bodily movements where the slope depends on how quickly things are escalating and the limit depends on what the mutual expectation for the night is. If you're both DTF, the limit does not exist. But, if you're intending to put a limit on what's going down (or should I say who's going down), then the math becomes tricky. Unlike mathematical equations, the two lines of this function to not always agree on the limit they're going to encroach. One member of the hook up almost always wants the other member's legs to split across the positive and negative side of the X-axis, and if that doesn't happen, they will at the very least want the other member to drop below their X-axis. This is often met by some hesitation from the other member of the hook up. This moment marks the most important point plotted on their sexual function; it's the moment when the hook up stops being mathematical and starts being physical. The numbers and logic disappear as the bed/couch/backseat turns into a wrestling ring. There is no more mathematics, no more words even, just a silent battle of strength and stubbornness. Just like in a wrestling match, everyone is wondering "who will go down first?"
The night starts out with the given exponents: girl, boy, alcohol, and apartment. Imagine you've been at a party when you start talking to an attractive guy. He's charming and funny to begin with, and the more you two drink, the more his attractive qualities exponentialize. You two are totally connecting, so as the party dies down you accept his offer to go back to his place and "hang out." And no, this isn't community college pre-algebra; you're not a fucking idiot so you know that by "hang out" he means "hook up." The next thing you know, you're back at his room on his top bunk and the majority of your clothing has been subtracted from the equation. The slope of your drunken function has been increasing rapidly, but you've mentally solved the equation by deciding that you're not down to fuck, but rather down to foreplay.
"Hold on, let me get a condom," it seems that he got a different answer.
"No, no, not tonight," you say. He's disappointed but accepts your answer, and so you two carry on the nakey-making-out.
You're drawing nearer and nearer to your limit, and are looking forward to the point at which you can blissfully pass the fuck out. He then makes the move from being on top to pulling you on top of him. Now that you're on top of him, he first puts his hands in your hair (aw) then moves his hands onto your shoulders, also known as his key leverage point (ugh). Now you're under pressure as he gently yet firmly pushes down on your shoulders. You've arrived at "The Limit." Numbers and slopes don't matter anymore, you're engaged purely in a test of physical strength and stamina as you resist the downward push from a pair of hands that you met all of three hours ago. Like any good athlete, motivational phrases run through your head to help you find the strength within to keep fighting. Does he even remember my name? Do I even remember his? Will he return the favor after, or just roll over and pass out? This room looks familiar- have I been in this same situation, only on his roommate's bottom bunk? Somehow, your thirty-minutes-on-the-elliptical-only-on-days-you're-hungover conditioned body is withstanding his fratty, swollen biceps. Neither of you have budged and both of your muscles are beginning to twitch. It's pretty awkward now.
Depending on how big of an asshole your opponent is, once he realizes he's not getting head he might pull a line like "Hey, listen, I gotta wake up really early to start tailgating tomorrow, so I'll see you later," or he might roll over without saying a word and pass out with you just lying there. Chances are he won't be happy that you won the wrestling match, which is why it's always best to leave and not sleep over if he doesn't kick you out anyway. Celebrate your victory on the shameful 4 am walk back to your room. The important thing is to not fall asleep at your opponent's place after winning the wrestling match. No one likes a sore loser, especially when they're cranky in the morning and don't even remember your name.