This is more of a weird art than a type or bug: Your frotting/scissoring is depicted with legs bent back; that’s not a plausible pose except for Weird Barbie.
In reality it is one leg under the other, so that pressure is built up on the hip muscle/pelvic bone against each other’s genitals. They’re near each other, not directly touching.
(I know, asking a lesbian to describe a rare sex pose that’s more common in porn than reality but still…)
This pose also works on boys, rubbing the leg behind their balls. It’s just one of several types of mutual mastubation, usually used in concert with.