There are a lot of different kinds of sex: hot and heavy, slow and sweet, quick and comfortable, etc. They can all be fun in different ways, but there are certain kinds of sex that bring a couple closer and closer together in their relationship. Here are a few of them.

Having sex with the lights on. Most one night stands or first times happen late at night (not to mention that sometimes, they're in a booze haze as well). But once you've hooked up in broad daylight (and with a clear mind), with all your flaws out there to see without a veil of darkness, and you still find each other attractive? That's intimacy.

Middle of the night sex. The kind where you both half wake up and just can't keep your hands off each other at 4 in the morning. It makes you feel like you're totally in tune, even in your sleep.

Trying something new. It can be scary to experiment with something you've never tried before, making you feel vulnerable and nervous. But doing so together, especially if you talk each other through it, ends up making you feel more comfortable with the other person in the end.

Really, really comfortable sex. The kind where you've been together for so long, you've got it down to a choreographed routine, down to the minute, and you both get completely satisfied. Of course, you need to break out of this sometimes or you'd get in a rut, but sometimes, being so damn efficient together makes you want to high five each other for being perfectly practiced together.

Doing it in total silence. Whether it's because you don't want to wake your parents while you're visiting home for the holidays or because you live in a tiny, cramped apartment with multiple roommates and thin walls, having sex when you can't make any noises forces you to learn to communicate with each other in different, more intimate ways than you might be used to, using eye contact, your hands, and just remembering how well you know each other.

Sex that goes wrong. A cramped muscle. Falling off the bed. A, um, problem with liftoff. These things happen, and they're embarrassing, but once you've blushed and laughed and gotten over it with a guy, you're closer than ever.

All-day sex. Not literally, because you'd pass out from exhaustion. But the kind of Sunday where you stay in bed all day, sleeping, watching TV, making out, talking, and of course, doing it, stopping only for snack and bathroom breaks. Unsurprisingly, the kind of sex where you can't bear to leave each other's side makes you feel a lot more connected than the kind where you get dressed and leave five minutes later.

Doing it for the first time, period. Even if it doesn't lead to a relationship or even feel very meaningful, this person still knows you now in a way that only a pretty small portion of the world does. That doesn't mean the same thing to every person, or with every partner they might have, but it means something.