When a guy has a boner, and doesn't want anyone to notice, he quickly puts his hand down his pants and places his dick between his stomach and waist line. The penis should be touching skin and cloth.
Nick: Yo Nobs, your mom gave me a boner again!!
Nobs: What did you do?
Nick: I used the tuck.
By Florence
The Tuck
When a male has a huge erection and doesn't want anyone to see, they simply tuck the penis in between the top of their pants and their stomach, thus hiding the boner.
When a man tucks his penis instrument between his legs, thus mocking a vagina, also known as a mangina. Also the tuck is very oftenly brought up by people usually with the name of Jesus, they fantasize about it, talk about it every day, and very possibly dream of it.
I was tucking in last night on Sara'shairy muff and her clit came loose, I didn't want to say anything so I swallowed it, I still don't think she knows