We began with a CB 6000 and then also went to the CB 6000 S. My wife and her Man quickly learned to enjoy having me locked up. Unfortunately due to the closed design of the plastic CB series, I soon had skin irritations also. It was constant maintenance to keep it clean and dry but after7 to 10 days I had to be released due to the rashes. I soon learned to keep on top of cleaning it, usually twice a day, but still it was a problem.
We did learn the hard way, a few things. Obviously keep it clean, washing it out as often as possible. Next was keeping it dry. The high humidity environment just helps bacteria grow, causing rashes, male yeast infections, and the annoying funky smell. I used to dry it out with q tips and sometimes with a blow dryer. After urinating I would dry the inside with toilet paper by pushing the paper into the hole in the end of the tube. It helped. Lastly I discovered that Lace panties also helped keep the humidity under control, as opposed to the regular cotton panties.
In short, keep it clean and dry. Still, like I said, my usual lockup was only 7 to 10 days due to the inherent problems with the enclosed tube design. After exploring chastity for a year or so, my wife and her Lover enjoyed it so much, it was decided that it was going to be a longterm lifestyle, we just had to get past the hygiene issues with the CB series. Not that there's really anything wrong with them, the CB was a great starting point to find out if chastity is right for us.
We soon graduated to the Jail Bird from Mature Metal. The open stainless steel design solved all my skin irritation and rash issues. It doesn't have to be removed for cleaning and can easily be cleaned with a scrub brush in the show. After a couple of weeks, even lube wasn't required. It was worth every penny. This thing is designed for longterm chastity.
I hope your keyholder enjoys the CB 6000, it's a great starter, but if she decides to make it a lifestyle, there are allot of other designs and manufacturers out there.
Best of Luck, and of coarse the old saying is certainly true, "Be careful what you wish for"