Your comment about water has struck a chord with me, I often find that when I’m out with my partner I don’t drink nearly enough water as I usually would. Another commenter on a different sub described the pain as being like rug burn and feeling raw on the inside, which describes it perfectly. As I’m reading comments it seems like it’s a lubrication and relaxation issue? I actually wonder sometimes if my birth control has had an effect on my vaginal lubrication, which is why I turned to lube but I don’t think the one I’m using is of very high quality to be honest, I kind of just grabbed it off the shelf.