1. As far as I know, silicone dolls aren’t made that way. Silicone dolls are molded differently than TPE. So, no plugs in silicone vaginas.
2. Absolutely no effect on your experience whatsoever unless the plug comes loose while you are doing your thing. TPE dolls are poured with a hole at the top of the vaginal cavity up to the skeleton and it’s normally sealed by the manufacturer with a plug of TPE to prevent fluids from getting inside the doll.
3. It depends on the type of vagina an insert doll will have no effect on performance however I’m assuming a fixed doll having the same TPE plug, this would create a vacuum when having sex and could pull the plug if it’s not glued well and then the vacuum would disappear. It’s the same as those mouth toys with no hole on the end they literally suck down on your junk to mimic a blowjob assuming the entry hole is very small as well.
