To clarify, I am not totally against cuddling with friends. I have done it, but am just not very much into it, and would only do it if completely spontaneous -- but I would be on the lookout for sexual overtures. I don't have a set of friends that I consider "cuddle friends" and it's very unlikely that I would ever cultivate that.
There was a good friend I had, back in the 80s, whom I used to call my "Harry Met Sally" friend - meaning that we were good, very tight, close platonic friends yet had a wee bit of unacknowledged attraction (and sexual tension) between us. We never ever wanted to go there. Actually since I knew him so well, I also knew I'd never want to be in a romantic rellie with him - I saw what a PITA he was with his girlfriends! Haha. But we very rarely would kind of cuddle -- not with our bodies wrapped around each other but just sort of laying next to each other while reading or something, with my head on his shoulder, etc. One day we got into the cuddling full-on, and it led to some French kissing and ugh, that was it. The friendship never recovered. The next time he saw me in the street and we hugged hello (as we'd always done before), he grabbed my ass, and I had to smack him. He told me that I asked for it with my tight dress and behavior. I broke off that friendship immediately.
I am a big hugger and caresser. I like hugging people, and when I am out with someone, I will reach out and caress or stroke their arm or back, or play with their hair, in a totally nonsexual way, and only if I sensed openness to that. I also will freely give shoulder/neck rubs and massages (ex-bodyworker with strong hands here).
I feel that if you really want sex with someone, then come out and say it. Don't hide that desire behind some other activity like nude hot-tubbing or cuddling. I don't mean to imply that everyone into this stuff is using it as an excuse to get their jollies, but I think more people do than don't, and they/we just don't want to admit it.