Possibly the most versatile word in any language. Though it sounds like "some b word I'd like to fuck," bilf actually refers to semen, but can be used much like fuck in that while someone can be bilfing, can bilf all over the place, can be full of bilf, and can be bilfed upon or into, they can also be referred to as a Bilf.
Damn hot mama, I'm gonna bilf in your bilf chalice.
Steve: So he stole all your shit?
Steve: What a bilf
You bilf nugget
you bilfing moron.
I'm gonna fill you with so much bilf you're going to get swimmers ear.