The act of trying to hide an erection by tucking your penis into the waistband of your pants. This method is usually used when in public and/or wearing loose fitting pants or shorts.
I got an erection while staring at that woman but i was in public so I had to tuck up.
The act of twisting and tucking your hair inside of a hat or some sort. Then when you take the hat off your hair cascades down your back looking beautiful. (See the Princess Diaries movie)
Princess Diaries Tuck-up-
Just put your hair in your work hat like the "Princess Diaries tuck up", so when you're off you can whip your hat off and shake your hair out and yell "I'm off work bitches"