felt like butter

Synonymous with "felt very smooth"
Likely an altered version of "smooth as butter" or similar phrases.

Used to compare how an action felt to the feeling of butter.

The earliest online mention i found was an old man asking about the phrase on a forum in 2017. Everyone who responded said that it was not a figure of speech that people use, so presumably this is a very recent, rather rare phrase.

"That snatch felt like butter"

"That 360 no scope felt like butter"

"That muscle up felt like butter"