Cowgirl problems

[gasmaskbandit.livejournal.com]

Okay, so my boyfriend doesn't mind missionary, but he wants me to climb on top every once in a while. I totally want to do this for him, but here's the problem. I don't know if my legs are out of shape, or if the bed sinks in too much, or if I'm simply not doing it right, but after a bit of thrusting my legs start to kill, and that's all I can feel. Totally boring, painful, and pleasureless.

Help me?