I was thinking of Peevee's BBC Sherlock story "Just a Little Bit" (which doesn't even use the tag, as it turns out) and it's a total id thing for me - experimental, greedy, we're going to set a boundary here and this time we're totally not going to blow right past it, right? Uh, oops.

Interesting that the tag is clustered in one fandom! Bet that's common and I just haven't noticed.