Pit Bubble
The bubble created after ejaculating a good dose of semen (approx. 3oz) into a willing partner's armpit while the arm is slowly raised.
My boyfriend was armpit fucking me in the back of the class room. It was ok. He liked it. Suddenly I was distracted by the professor's question so i raised my hand. I was happy I knew the answer, but embarrassed when everyone saw my pit bubble.