A rule of the utmost priority for any outstanding gentleman/someone who wishes to not be murdered in their sleep.
Baz: I barely escaped with my life last night, this girl I used to sleep with came after me with a machete!
Gill: What did we tell you?
Baz: ...Don't stick your dick in crazy.
Gill: Don't stick your dick in crazy.
A relatively recent but perennially true maxim, advising one to refrain from sexual congress with the unbalanced.
Bro 1: Dude, that girl with the Tori Amos shirt is HOT.
Bro 2: Bro, bro, always remember: Don't Stick Your Dick in Crazy. Here me now and believe me later.
When someone needs something that only a colossal ahole can provide, instruct them to take a deep breath, gather themself, and as they head off to certain doom, state, "Well, time to stick your dick in a beehive."