[ila]

If I am with a shemale I would let her decide which way she wants it. It's not up to me to tell her to tuck her cock back if she doesn't want to. I'm sure that it's not the very comfortable for a person to keep their cock tucked back for any great period of time.
As to my personal preference though I like to see a bulge. It's looks sexy to me when a beautiful shemale is wearing a dress or bikini and there is a hint of cock showing.