Well I'd be struggling to get the thing up with two hands.
And Jen, well, I might be untrendy, but I'm not dense and I just thought of googling them (LMAO and ROFLMAO) and now all is clear.
Now I'm just left wondering why we (read - trendies) went to the trouble of making up abbreviations for expressions that we never used to use anyway. I mean, did people used to be say they were Rolling on the Floor Laughing My Ass Off when someone said something funny? I don't remember that at all