to make someone uncomfortable enough to share whatever they have with you. Such as to stay at someones house long enough for the host to feel like they should ask you to stay, and then eat all their food after they are asleep.
Friend: Hey, can I schwade up on that bag of chips?
You: You need to get your own man.
or
I could hear him in the kitchen schwading up on all my food after I went to bed!
Taking really, REALLY immense delight in the misfortune of some loathesome person-like creature. Well beyond garden-variety schadenfreude, a case of schadenboner lasting beyond four hours means the tumescent owner must seek medical attention.
The final exposure of Dan Rather as a failshit partisan back in 2004 gave me a 3-hour schadenboner..at least.