Verb: to perform an indeterminate sex act of a very dirty nature (indeterminate because no one can fathom the sexy depths of its dirtiness), named so because "scrapapple" just sounds dirty, doesn't it? Scrapapple parties may involve numerous individuals, who (it is believed, since scrapapple parties are very secret) take turns scrapappling. It is a mix of the words scrabble and apple, for mysterious reasons.
"Girl, you're so fine, I want to scrapapple you!"
"Dear Joe, You're invited to our scrapapple party, as long as you sign this confidentiality agreement."