The hilarity of the ensuing permastun pwnage upon obtaining two sets of Cranium Bashers on heroes such as Troll Warlord and Mortred in the online game DotA.
Related to ROFL, a ROFLASM means both to laugh so hard it comes close to orgasmic in its quality, and also literally abbreviates the phrase 'Roll on the floor laughing and shat myself'.
"That was so fucking funny, I just had a ROFLASM."