A Wiss is a portmanteau of Wimp and
Piss...
The Word means a "Wimp who drinks Piss"...
This is the sort of albatross that gets hung around the neck of somebody who is bullied and then supposedly made up with by being bought a
beer. Said
beer, however, happens to have been dosed liberally with piss... This happens after the victim has been gotten drunk enough not to be able to prevent this from happening...