A truffle snatcher is some one who steels your girl, whom you spent time on, getting them horny and wet.
For example: You're talking a hot girl at a party. You have been flirting for ages and now you are ready to "go up stairs". But then the "Truffle snatcher" comes and snatches your girl and shags her. Because she is a horny as a nun in a cucumber field.
by J-Dog Official March 21, 2014