This site is neat. It has a variety of packers and STP tubes and so forth to chose from. They give you some guidelines and so on. It looks a bit better than the standard Mr.Limpy model.
http://www.thetransitionalmale.com/stud.htmlI bought an STP fitz. I can use the nipple device-- but too be honest I am not too good at any of them.

Anyway, you can google this one. But you can get this with the Sailor. It is not as expensive as the Peecock but still more than Mr. Limpy stp.
BTW, as for passing with these. I'd use caution. I think that if someone caught a tiny glance of these, you could. Men don't seem to stare when using the bathroom. OTOH, there might always be the outlier. I think that some guys are so bold they use a medicine spoon in a urinal. I don't know if that is really recommended but it has been done.
--Jay