Chastity and orgasm denial discussion

My partner and I have been thinking about chastity for a while, and we recently purchased our first device. As bargain hunters, we went with one of those standard wire cages that run the length. It resembles this: Pay attention to the “peg” which secures the lock and holds everything together. We quickly found out that once locked, it’s nearly impossible to take off his body. However, when he is flaccid, the rear ring slides down sufficiently for his penis to slip out of the top opening. So while the device remains attached, it doesn’t do much good. We’ve looked into “pullout,” which is what this issue is called, and are now exploring solutions. Currently, we’re weighing the Points of Intrigue against the KSD-G3. Both seem like they could fit inside our cage and have a hole for our device’s “peg” to pass through. However, there are two hurdles with either option. First, we aren’t sure if these accessories will work correctly on our specific model, and second, we’d prefer not to spend around $50 on one of them, especially since that’s roughly what the original cage cost. Do you have any more affordable suggestions? We’ve thought about adding extra padding (such as a sock) inside the cage for a tighter fit, or crafting a mock-POI from one of those spiky rings found on water bottle necks. Any advice would be appreciated. Thanks, Puella EDIT: It turns out he can slip out even when erect, not just flaccid. Not ideal…