I also have a very tilted uterus- my gyno couldn't even find my cervix for a good 10 min during my last pelvic exam. I experience EXCRUCIATING pain during menstruation. My boyfriend is average sized, and even when he's very very gentle, with adequate lubrication, sex is horribly painful. This is so sad. I want to be intimate with him, and in the past, we have had amazing sex, and the feeling that accompanies is out of this world. This problem has gradually gotten worse. The past weekend we were out of town for a little mini vacation, staying in a very nice hotel, and we tried to make love and I ended up bawling my eyes out and couldn't get him withdrawn quick enough. It doesn't seem to matter how deeply he penetrates at all, or how aroused I am, it's horrible. We've tried countless positions and the only a few seem to provide any kind of relief:
we lay on our sides facing eachother, I place my bottom leg over his shoulder (I'm fairly flexible)or with my knee against my chest with my foot on his chest and my top leg around his body or at a 45 degree angle with my foot flat to the bed, and he slowly penetrates and grinds against me. I don't know if it's the angle that does it, but it feels great, nealry pain free, We both reach orgasm, and it also provides excellent intimacy: we can see eachothers face, kiss, and explore eachother with our hands.
Sometimes, another position that works fairly well is like missionary, except legs bent at a 45 degree angle, knees towards my chest, angled to one side.
Also, a variation of spooning where my body lays at a 90 degree angle, bent at the waist, legs parallel to him, with one leg draped over his hips. This doesn't feel as intimate because our we can't kiss or look at each others faces, but it feel wonderful, and he's free to use his hands for manual stimulation.