Nisflip
A Nisflip is a type of movement in which Mario performs a sideflip and dives on the same frame. The name "Nisflip" is a reference to a TAS by 4232Nis. This is almost always not ideal except in case of very short distances, if you would lose your 32+ speed within travelling less than 1246.9 units after initiating the sideflip.
After a sideflip, it is best to wait until Mario reaches just below 32 speed before initiating a dive. This is because acceleration decreases if Mario passes 32 speed, so the +15 speed gain from the dive is more valuable at 32 speed to reach 47 speed, rather than, for example, to go from 8 speed to 23 speed.