>>5797739It's a pair of technic connectors attached via frictionless pins, then using a System pin piece, usually heresy'd, along with a 1x2 axle to hold the nuva armor.
>>5797742>>5797752NSSD's ass design is intended to be articulated; the rubber or elastic keeps the asscheeks in place, meaning that they'll hold to poses but won't flop around.
Some have parts cut off, most, however, don't, as it isn't necessary.
The pins that are used to hold the cheeks also allow for them to be posed as being peeled apart.
It's quite possible to figure out how some of these things work just by looking, NSSD takes a lot of pictures and has a fuckton of MOCs.