First of all, I'm going to be getting an IUD (Paragard, if it matters) soon. Can I keep getting fisted if I also have an IUD? I'm sure I won't feel like having sex at all for a while, but I don't want to give up fisting for 12 years, either.
Second, I want to switch from using tampons to using a menstrual cup. I'm in my early 20s and I haven't had a kid, and usually the cups that I've seen have been marketed as 20s/no kids vs. 30+/had kids. Does fisting stretch out your vagina? I haven't really noticed it in myself, but I'm wondering if I should get the 30+/kids style because I might be stretched out.