ROFLWUIM is an extremely creepy acronym used while flirting via instant messaging, texting and other non-verbal communication methods by females and or gay males, in most cases after a joke is told by the person being flirted with.
Like its parent acronym - ROFL, ROFLWUIM can be combined with other acronyms or expanded by adding additional letters.
ROFLWUIMWESWTFBBQ- Rolling On The Floor With You Inside Me Whilst Eating Steak and What The Fuck Barbecue Sauce
Guy: "(insert hilarious joke)"
Flirtygurl57: "You're so funny and cute XD. I want to ROFLWUIM"