Office injections question

New here. Sorry in advance if this is a silly question. my prescription of trimix arrived yesterday. I have my trial injection at urologist scheduled in 8 days. I dont need a lot of help from Ed meds as I have function just never hard. Always spongy. Oral meds don’t do a thing and side effects are many.

My question is this. After you receive the injection does the urologist keep you there for the duration of the effect. Or do they just administer the dose and send you on your way? I’m larger than average both length and girth don’t really what to sit in an office with boner wrapping around my hip. lol.