A person who smothers fun.
Likened to a fire blanket due to its ability to extinguish fun by asphyxiating it at an early stage.
Person A: Hey team, shall we do an almost naked calendar for charity?
Person B: Hell yeh, I love getting my slong
Person C: Yeh everyone will buy it to see hingers
Banter Blanket: No, absolutely not, we're not doing that.