Chastity and orgasm denial discussion

Greetings everyone, I’m typically quite creative, yet here I’d value your opinions on how a keyholder might notice if the wearer has yanked his penis free from the chastity unit. I own a CB6000, an eBay metal CD, and am currently locked in the Holy Trainer. Of these three, the HT is certainly the most comfortable. I also have a DreamLover 2000 attached to it. Still, I can manage to escape from all of them with just my penis (the balls remain securely trapped). I’ve tested numerous methods to physically stop the cock from being pulled out, but none worked well. Since my girlfriend is both my Mistress and keyholder, is there a way for her to tell when I’ve been naughty and touched myself without permission? The only idea that comes to mind involves her writing or drawing with waterproof lipstick at the base of the penis. If I pull it out from the base, the mark would smear. And if she spots that, I’d face 200 cane strokes so I never dare repeat that mistake. Any other ideas?