Moffling is the act of smelling a pair of underwear, only to find out that they have been used and therefore smell terrible. One who dives into his/her own underwear and discovers this smell is said to have been moffled.
Chuck: Oh god, those undies were like a week old.
Brad: Dude you totally moffled yourself.
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Pam: Are these undies good?
Rodney: Give 'em a sniff. Don't moffle yourself!