Any success with 'casual' sex?

So as a demi, I have never really been interested in or able to have a casual sexual encounter. I have had some 'one night stands' I guess, but only because I was hoping for it to turn into more. But now, I am at a place in life where I really don't want a relationship, but think that I would really benefit from some kind of sexual fling. (Cause it's been awhile, and I could honestly use the reassurance of someone just being into me). Obviously the problem is that it takes me a while to feel comfortable enough with anyone for that to be on the table, but I don't want to give anyone the impression that I am looking for anything long term either. Have any of you demis had success with manifesting a purely sexual relationship with anyone? Maybe an old friend or like, an ex that you've maintained a friendship with? I feel like, as long as I trust them and know them a bit that it could work...but with anyone new it seems impossible!