When the vet comes out have Her/him check him out and give advice on how offten her will need cleaning. You could pay a vet to come out each time( I know folks who do this) or you can clean him up yourself. Vet will show you the proper way. I only have mare's so sorry I can't say. Just gotta be careful an make sure the horse don't mind you messing with his "junk".
As for the other folks here, Don't feel bad! Heck I'm a guy and I check/clean my mares "girly parts" jsut about everyday. Lucky for me my girls don't mind me cleaning them, I think they like it cause I'm sure it feels good to get that dirt off them. As for the funny "date night" comment. Don't feel bad, Gypsy does the same thing. Somedays soon as I "touch" her there to cleasn her, She will squat, hike her tail up, wink like crazy an dribble pee some times, nicker and Look back at me with love in her eyes. I just laugh, shake my head. Horses you gotta love them.