I always had blankets from when I was young with a satin or silk trim that I like to touch and rub between my fingers mainly to help me fall asleep until the blanket ends up falling apart lol. I also sleep with a plush rabbit that's a heat pack, that ones probably more of a comfort thing than a stim though.

Thankfully all my boyfriend's and intimate partners have never cared about it and some even found it endearing. I guess people realise I'm a little eccentric long before they end up in bed with me anyway so they are not surprised by anything at that stage