1. You're doing something you saw in a movie that in fact is very uncomfortable. Yeah, it looked good in that rerun of Gossip Girl you watched last week but in actuality, your leg keeps cramping and you kind of can't feel your pelvis. Skip.
2. You're choosing your position based on how thin it makes you look. If your primary concern is whether or not you look model-thin in that position, the odds that it's actually going to be effective in getting you off are fairly slim. Plus, if you're not sleeping with someone who thinks you look sexy in all positions, thin or not, that's a bigger problem anyway.
3. You tried a different position one time and came right away. If you have one go-to position that in theory you think should work for whatever random reasons you assigned to it ("this way, if I want to grab a water, I can!"), but it's never actually that good, and then one time you ended up in a different position to a hilarious degree of success, maybe drop your preconceived notions as to what works for you. And to that end...
4. You're not actually getting off. If you're having sex in one particular position but never really getting off in that position, or when you do, it's like climbing a clitoral Mt. Everest that involves 20 minutes of intense focus, that should be a pretty good indicator.
- You're trying not to mess up your hair.** This goes back to no. 2 but has less to do with your body and more to do with the idea that somehow you're supposed to have really intense sex while your hair and makeup stay perfectly in place. This is not a fucking thing and you're ruining everything for yourself by aiming for it.
- You always let your partner pick the position.** The odds that he's going to only pick positions that allow you to feel the best possible way are slim since he is not in your actual body and probably doesn't even know what those positions are. Don't leave it up to him! Flip him over and get into a position that feels amazing for you. Trust me, he'll be into it.
- It makes you feel disconnected from the experience.** If you spend most of the time in that sex position trying to figure out a way to make your leg bend backward like your childhood Barbie doll just so you can "get it right," there's no way it's going to end in awesome orgasms.
- It's straight-up painful.** Sex should never be painful — unless it's purposeful BDSM pleasure-pain like spanking — so if something hurts, talk to your gynaecologist. Even if there's not a bigger health problem, she can recommend positions that might work better for your body (and just because one position doesn't work for you doesn't mean you're broken. It's just not your thing. No big.)
- You're making eye contact with someone who is not your sex partner.** If you can see your neighbour Jerry through the blinds, time to make some adjustments. Also, what is Jerry even doing home?