Yes...they...can.

You know, for an old thread, this is getting REALLY interesting! Does PrncAlbrt have any further suggestions?

(And to Lady Amanda: Your tie-down idea is a good one. Since his penis has to be pulled back past his scrotum, you can seperate his balls to either side, giving easy access. As he hardens there'll be (in addition to everything else) a strain on the suspensary ligaments that will be attempting to hold his penis erect against the pull of the string between his legs.)