How I agree with you!!! When I first had this experience, it was the most incredible feeling! Feeling this chain slide inside, filling me up and feeling the weight is insane, but especially when it comes out, the vibration of the links makes me totally crazy with pleasure. Every time I'm fisted the chain is obligatory...
Been a few years, but a fuck buddy used to use a chain on my ass. I managed to take over 4 feet at a time and it was amazing, feeling that heaviness growing in me and then having him slowly pull it out; that sensation is one only experiencing it tells how fantastic it feels. Somewhere between sublime and the most stimulating act imaginable. Never failed to blast cum out while the chain was being pulled out of me and feeling it slide on my prostate and sphincter.