The act of masturbating at an extremely inappropriate time, with little respect for the feelings of others in the vicinity
John: Bob, we're at a fucking funeral, stop jerking off in the corner!
Bob: Why? Masturbation is perfectly healthy!
John: That's not masturbation, that's crassturbation.
Bob What's that?
John: Look it up on Urban Dictionary.
by derpymuffins June 18, 2014
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