Refers directly to Till Lindemann, lead singer for the German Industrial band Rammstein. It refers to the fact that he has put on a little...erm...Weight and it isn't muscle. Also refers indirectly to someone who has put on a few pounds.
He looked a bit like the Tillsbury Doughboy in their video for "Mein Teil" didn't he?
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.