The act of "stamping" and individual with the wet tip of one's penis (usually due to a mix of semen and vaginal secretions), preferably on the forehead. Similar to a mushroom stamp only juicer and more degrading.
"What happened last night? I feel terrible and there's some sort of funky residue on my face. Did somebody give me a Wet Stamp?
by the dude abides February 22, 2012