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1. BYOL
Bring Your Own Liquor.
"PARTY TONIGHT, BYOL."
2. BYOL
Acronym for "Bring Your Own Lube"

This might be specified if one was inviting peeps to a swing party where personal lube would be used for sexual purposes
BYOL if you are into Greek sex.
3. BYOL
Bring your own legs
Dude this party is BYOL
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