Sex after injection to get erection?

[puzzky]

I'm going to a urologist soon which is going to do an ultrasound.
He might inject a substance to give me an erection.
I am visiting my long distance girlfriend the day after and I'm wondering if can have sex after the examination?  

[jj21]

Should be fine. I had sex an hour after my injection - i actually couldnt get my penis down. The doctor recommended to have an orgasm if the erection wouldnt subside.