The OP specified, what if you wake up during it? This has happened to me once. I woke up, but near the “end”, at the point where it was already too late to simply stop - right before orgasm, where if you stop, you experience great pain and discomfort. (I don’t know if there’s a name for it in women, but I believe they refer to it as “blue balls” in men) In my case, I waited and did nothing to see if the feeling would go away, but it just grew very painful. Literally moving my legs a little was enough to “finish” so that the pain would go away. I confessed this as soon as I could, and the priest said it was probably not a mortal sin, but I literally don’t know what else I could have done. The pain wasn’t going away. All I did was move a little, and wasn’t trying to commit self-abuse, but I feel like maybe I should have done nothing and just hope that the pain would eventually stop.