This sore keeps coming after sex

I don’t know what the red thing is, but I think you got GW too. I saw one

I’m not set on genital warts as the diagnosis after noting the same lesion as the last commenter, that might just be a skin tag. I would speculate that your open sore is related to friction or, more likely, a tear as I see a flap of skin rolled up. This can be caused by a few things: not enough lubricant, the size of the penis, roughness.

i agree with Bradlay89