A person, male or female, who is situationally insensitive. Also known as, someone who does things that are inappropriate regarding the current situation. Many things wine baggers may do are considered party fouls.
"Matty is such a wine bagger, he pulled out his dick in my kitchen when my parents were around!"
Someone that doesn't stop complaining/moaning and in most cases doesn't realize they're doing it.
You cannot get throught to a wingebag because their head is up their arse and love giving out.
Jesus, it was tough listening that wingebag go on and on after I told him I can't help him out Saturday.