Refers to a twitch.tv meme that cropped up around SGDQ2015 where, during a Super Smash Brothers Melee tournament, a player walked up to the opponent on the edge of the map and simply “down-smashed” him. The commentators reacted with hilarity and disbelief stating, “You, did he just walk up (pause) slowly and down-smash” and was replied with “He did, he really did though”.
This, later, because a spam-meme during the SGDQ event where viewers would replace certain parts of the quote with relevant information, such as “Did he just walk up slowly and ledge grab” during a clutch situation, and often broken up with emotes.
Most commonly, the emote "" is used between each word like “Yo did he just walk up slowly and bow tap” (best represented with the KappaEverywhere extension).
Relavent video highlight: https://www.youtube.com/watch?v=3NMhGCf20i0