Originally derived from the TV series I Love Lucy, splainin' is now used by gamers as a put-down to taunt their opponent after a crushing defeat.

After one has been pwned, he/she has some splainin' to do.

Can also be used to describe anyone who looks absolutely ridiculous or obviously has no idea what they're doing.
> Dude, i just beat you 8-2 at Fifa '95. You've got some serious splainin' to do.
> -I can't tell if that's a man or a woman, but it sure does have a sweet mullet.
> -I'd say they've got a lot of splainin' to do.