One very recent bus tour vid (MIRD-147) has a bunch of guys whose penis are a marvel to see, how SMALL they are. Luckily there was at least one guy who's manhood can hold up the vid. The girl Shiori something was sucking this guy while all the other teeny weeny men masturbate on her. Anyway I think the "physically capable" and "not creepy" requirements are very very relaxed in reality.
BTW other than the weak manhood, it's not a bad vid. Normally I am really not a fan of sperm, but in the aforementioned scene, despite all the tiny little penises, at the end there's a beautiful array of gooey splotches. Manga artists love to draw a girl covered with sperm, but it's the first time (IIRC) that I seen a good realization in life action AV.
for the small dicks I think studio try to make this movie so close to reality for physically capable at least their dick can erect and cum, for not creepy factor they don't use actors who look like red neck, psycho type right ?
overall I don't like this bus tour series, coz the action only gangbang, prefer other moodyz series that I mentioned above that had big orgy scenes, its more hilarious