When a partner does not know what a blow job is, so they literally blow on your penis, hence making your penis "chilly"
"man Mildred had no clue how to give head, so she gave me a chilly willy"
When you fill a condom up with ice-cream, not to be confused with a dirty-penguin, which is when the ice cream is consumed after use.
Oh my god my boyfriend game me a chilly-willy and i thought he was giving me signs!
When you put air duster upside down and blow it on your cock.
last night i did the chilly willy.
When you have sex in snow you pull out and scoop some up with your penis on the way back into a woman's vagina
Last night I had sex outside in the snow and gave my girlfriend a chilly willy
a penis that has been deep-fried, covered in peri peri then frozen
you've got a chilly willy
The single greatest feeling of pure adrenaline, induced through the snorting of vodka up one's nostrils. May get you intoxicated quicker and with greater effect.
Friend: Bro have you ever done a chilly willy?
You: No, what's that?
Friend: *proceeds to snort vodka and go batshit crazy*