I hope no one is put off by the fact that I am cross posting but I this little "hack" has really made my life easier so I thought I'd spread the word.
I ran across a posting on the "enforced chastity" group on Fetlife by a guy who said he was using an external condom catheter on the outside of his chastity device in order to control his urine stream so he could use a urinal. I figured this had to be worth a try so last week I bought a handful of the catheters from a local medical supply shop and here is what I've learned so far (for your reference I wear a Steelheart 2 by steelworxx):
First, its important to carefully center the condom on the end of the tube before you unroll the adhesive part or everything gets wrinkled and stuck together. Second, once unrolled, unless your device is huge, you need to trim the condom to be a bit shorter than the device otherwise the adhesive constantly pinches your skin on between the excess silicon and the edge of the tube.
The upside is that yes, I can use any urinal almost as easily as if I was not locked. I say almost because through trial (and embarrassing error) I found that you have to pull your entire package (i.e. chastity device and testicles) out of your underwear to keep the urine from back-flowing out the rear of the tube. I learned this on Friday though and have not had any leakage or issues since then. Cleaning has not changed, I am still able to use the shower tube to get plenty of soapy water in and out of the tube so the condom can be used for quite a while before changing. Unfortunately it does block off the vent holes so the stimulation I was able to get from the shower head is now gone - ugh! Well, at least I can still get that little pleasure between condom changes!
I have to say I think this is a real innovation and will certainly make my chaste life a bit easier to deal with for the long term.
I'd be happy to answer any questions so just reply or PM.