It's been a long time since I wore a cage with an insert, but it always struck me that when I'd leak precum like that how diabolical the tube was. Precum just flowing out of you and you can't even feel it passing through your cock, robbing you of even that little pleasure.
So far my wife has caged me for up to 2 weeks, with the catheter in my cock included, and the only problem I've had is that my balls fill up with semen and swell until my wife discharges them, or I do prostate massages to discharge them.