1) To violently smack someone in the back of the head, typically a female smacking a male.
2) To waddle and yak (talk) at the same time.
3) 'What i did to/with your mom last night.'
1) I'm going to yaddel you!
2) My english teacher is such a cow, she spent the entire period yaddeling.
3) Yeah, i yaddeled her!