|2.||Jack in a Box|
A penis that looks average until it is aroused and then erects to a size well above the norm.
Andrew: Yes, my penis looks only about an inch long when it is soft.
Slampiece: Well I must admit, your Jack in a Box was a nice surprise!
|1.||Jack in a box|
When you have an erection that your girlfriend doesn't know about and you whip it out of your pants and show her your hard on, usually with a really pleased expression on your face.
I was lying in bed reading the other day when Rob pulled down the sheets and sprung his jack in a box on me!