when you ask some friends to bid for an item you're selling (e.g. on ebay) they buddy-bid for you to force up the price.
A: "eh man, i got some stuff i'm trying to sell on the net. the auction's over in about an hour and it's still at $15.50. would you be so kind to help me out?"
B: "sure, dude. i'll buddy-bid on your items."
A: "alright, man. i o u some."