When an adolescent male gets an unexpected erection in public, and tucks said erection into the waistband of his pants or shorts in order to conceal.
"Dude, it was the WORST! I was walking down the hall to geometry class, and saw Jessica walking in front of me, and got a boner and had to Upright Piano, because I didn't have my backpack with me to hide it!"
by Carl Winslow is the Man June 19, 2019