The Parachute: Insert both fists and feet into your partner's gaping vagina/asshole and hold on for dear life, in the shape of a human parachute. This can be extremely pleasurable for many different reasons; The massive amount of pressure and weight on the walls of the selected hole are enough to cause orgasm, but the sensation of wriggling fingers and toes will be too much to bare.
Also a very useful way to build INTENSE MOTHERFUCKING CORE AND BACK MUSCLES.
Me: Your mom sure does like it when I get a parachute going up in that gaping pussy of hers.
Me: Did you see that parachute I just pulled off on your mom?