So...my boyfriend and I are trans guys, pre-hormones/everything, which really only matters because male pronouns. This is actually concerning him, but I'm the talkative one, so here goes:
After getting him off via finger penetration, I pulled my fingers out to find the tips covered in blood (it originated up inside, not around the opening). It didn't look like menstrual blood, plus he's mid-cycle and shouldn't be bleeding anyway. I use vinyl gloves for this, and my fingernails are short, so I shouldn't have broken anything, and he was adequately lubricated and he said he didn't feel any pain during or after. And it's not a UTI because he's had one of those before and knows what they feel like.
This is actually the second time it's happened, but there was more blood this time than last, and last time we blamed it on his cycle (it was around the right time). We're each other's only partners, we're both STI-free, and we're really careful about keeping our hands, mouths, and dildos clean. We've been having sex for two years now, and he's been fine with my fingers and our dildos (including both ends of a Feeldoe slim) before. We have been having a bit of a dry spell for various reasons, but we're not sure if that would matter since this didn't happen the first time we had penetrative sex.
My question is, with all that, we're wondering what the hell the blood is from and/or if it might be serious. He's not particularly worried about it, and he's usually pretty in-tune with himself enough to figure out if something is wrong, and we don't really have the means to just go get him checked out for the hell of it (though we will if there's a chance that this could threaten his health). However, it would be nice to have an idea of what might be causing this, especially if it's relatively benign.