I love blowing off right after girth work for a few reasons. But to address the main concern, does it effect gains? In my case, absolutely not (unless I could have gained faster somehow). I love doing girth right before sex as I am at my biggest girth size. Why not use it in sex, right? I also like to do length, every once in a while, right after girth to stretch tissues that are only expanded after a good girth session. I found shooting off, right after girth and right before length is the best time to stretch to make gains from areas not usually effected.