I'd just like to interject for a moment. What you're refering to as "mpreg", is in fact, FFM + mpreg", or as I've recently taken to calling it: "FFmpreg"
Silicone caulk smells like used socks that a sweaty dude used to wipe their armpits. The least appetizing of all the glues.
That's just engagement-bait. It doesn't need to make sense, it just needs to get people reacting to it.
I tried this method. I can attest that it doesn't work.
Only thing it gave me was a new kink