Fingers in his ass is a meme mainly quoted/said by Danganronpa fans on a site called tumblr or Danganronpa fans in general.
The sentence is usually associated with the pairing sansmaeda. There is also a thing called fingers in his all sunday. On Sundays people gather to appreciate the song fingers in ass and sansmaeda. On December 16th 2018, the day before tumblr's adult content ban fans of sansmaeda and fingers in his ass sunday celebrated what was called the "final" fingers in his ass sunday.
Origins:
On july 17th, 2017 user named skeletortilla uploaded a video on tumblr that had Nagito Komaeda from Danganronpa 2 and Sans from Undertale dancing together to a song called "ASSHOLE (FingerfĂĽckung)" made by BotanicSage on youtube.
Woody fingers is a term used by players at a poker table to describe a dealer they are not happy with - they are indicating that the dealer who may be male or female is not shuffling the cards correctly - they have woody fingers and the cards are remaining un-shuffled throughout the game. It is not so much a way of cheating as more of an indication of an incompetent dealer
'The Dealer on this game is terrible, Millie has told him ten times to cut the cards different but he doesn't- he's like a robot, the guy has woody fingers for sure'
'Mickey got so fed up with that woody fingers dealer he ended up ripping the cards up and swearing at him'