Verb. The act of clicking from tab to tab, usually from left to right, in a web browser. Social networks are usually a part of this, and people your chatting with get annoyed or say "Talk to you later" because they think you left when you were actually just cycling through your open tabs a bit slow.

when you've done something so cringe you can't stop replaying it in your head and it stops you from getting on with your every day life

Much the way we channel-surf on the TV or radio when we're bored, we also may be caught flipping from Facebook to Twitter to Pandora to UD. Hence tab-surfing. :)