I actually like including my balls… I get nice big plump balls and a nice fat cock. That said, (as Engineer says above) if you get a smaller diameter tube (at least to start), just a little bigger than your hard cock and one without a flange that’ll help. And of course if you get this smaller diameter tube you can certainly pump at higher pressure, get longer, just not as thick… but you should start slow, and gradually increase diameter to grow girth.