wait... you mean for example if she is in missionary to be more active...
Now that would be interesting and very hot to watch...
It is a matter of physics nateyes. She needs an effective way to hold on from something in order to move her body. The guy should also help her to keep the momentum. One of Lex Steele trade moves in the old times was to hold the girl in the air and then carefully let her body lean down. Her hand palms were touching the ground and he was still ramming her in something that look like an airborn missionary. It was very hot. I have seen some variations of this pose while both lovers were in bed. I even saw a few DPs in this way (these ones were some of the hottest scenes I ever seen).
Now about a certain adult actress who is doing often. I can't say for sure.
By the way, motion physics is something that directors don't take seriously in consideration and it is a pity because it can produce very very exciting poses.
Meanwhile... Explore Sexuality!
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