Introductions discussion

Hi there, I own an adjustable Cararra chastity belt that fits me well. When I’m highly aroused and erect while wearing it, I can occasionally reach orgasm by humping the device face-down on the floor. I want to prevent this from happening, even though it only occurs when my arousal levels are very high. Here are a few potential solutions I’ve considered; please let me know your opinions on how well they might work and if you have any other suggestions:

• Employing ClubFEM plastic spikes (not sure about their current availability as the site seems dated) to lessen erections through discomfort. The $40 price tag feels steep for a simple piece of plastic, especially since some feedback suggests it isn’t particularly painful.
• Applying lidocaine to my penis prior to locking up. I’m uncertain how long this numbing effect lasts.
• Wearing one of those desensitizing condoms before securing the device. Again, not sure about duration. (I would cut a hole for urination.) Which option seems most effective? Are there other alternatives to the $40 ClubFem gadget? (The 2-liter bottle cap rings are slightly too small for my comfort.) Thanks!!:)