I guess it all depends from person to person, when I was on anti depressants (+ sleeping pills) I couldn’t get hard if I touched myself. It was like my penis was in a deep sleep. BUT, I had a girlfriend during my anti depressant and sleeping pills, and although I could not even get it erect for 5% manually, when I was with that girl, I always had a hard on. Until today I haven’t figured that out exactly.
Don’t take me on my word about ballooning, but perhaps it’s better that you use some lube. In my case this makes it easier to maintain a proper erection.
It is said that you shouldn’t stroke while ballooning, but instead only using your fingertips. I couldn’t maintain a proper erection when using my fingertips so I had to stroke.
After putting some lube and wrapping it around my penis and on my hands, I did ‘half strokes’. Meaning each stroke ended under my glans.
Because of the lube I was able to maintain my erection and it was actually pretty damn hard. Though after about 10 minutes I lost it and stopped.
I think that if you really can’t get it up again while ballooning, you should stop. But that’s only my guess, and who am I?! ;)