A tax that is charged to a "friend" who is an asshole for one reason or another (such as cock blocking
, never having money for bills, is literally an ass to you, or other such reason that will piss the Taxer off) or for debts owed. Asshole tax does not have to be of monetary value but needs only to be something that is worth something to you or the asshole.
For instance, you may take an ex-roomates computer as asshole tax since that asshole never paid bills, ate all the food, and banged your girlfriend.
If the taxee wishes to get the taxed item back, i.e. he wants his computer back, he may trade the taxer something of equal or greater value(value being worth something to you e.g. you don't need his computer, but you do need an iPod. You trade his iPod for his computer. The computer being worth more money, but the iPod being worth more to you.)
Be warned that severe assholes may try to recover taxed property through legal means, but don't worry, the law is on your side because everyone hates asshole.