This is maybe more of an informative Ask. My understanding of Mina’s quirk is that while, yes, she can secrete acid, it’s voluntary (she can even run out of she does it too much), but also the acidity is voluntary. She has a non-corrosive form of the liquid she uses to, like, skate around like she’s wearing socks on linoleum, which is just slippery. I’m not 100% sure if she has to use her hands and feet to release these liquids, but it makes sense to me she could use them to self-lubricate her pussy and asshole (but at the very least she could use them for handjobs and footjobs, like she mentions here).
Best view i have ever seen !