Functions in the same way as 'fuck off' or some other expletive which expresses disdain at another or a desire for them to leave/stop talking/stop messing around.
Synonyms for cock off
On this page, you will find 30 slang terms related to cock off. Some of the top words include: blow a goat, jag-off, suck dicks in hell, frosts my balls, buh, and 25 more.