As far as I’m concerned, great sex is a function of trust, affection, candid communication, and, above all, fun. It’s a delicate balance. A fragile ecosystem. If I were any good at math, I’d draw a diagram or something, but alas, I majored in writing. So I draw the line when I’m not having fun anymore. Simple and easy to communicate. I expect my partner to understand and respect that. Because if you’re not concerned with whether I’m enjoying sex or willing to ask me if I’m having fun while you’re fucking me then, um, you shouldn’t be fucking me. There’s the door, dude, happy trails to ya.