Night Locking Challenges and Adjustments

Starting with cage details; Mature Metal and Watchful Mistress model. The shaft measures 2 inches long, using a circular ring (with vaseline applied) I’ve been training for some time now. He has managed several weeks of comfortable all-day locking successfully (unless the kids get rough with him, in which case I have him remove it to take a break during the day). Now we are attempting night locks. The husband achieved successful night lock this week, marking 3 nights total. I’m very proud of his progress but remain cautious. His first attempt involved elastic straps; he had to remove them after a couple hours because he disliked their feel (it was a three-point setup: the ‘belt’ plus two leg straps looping around each butt cheek to connect back to the belt). He wore the cage during the next day but slept without it. He tried again the following night, using only panties with no extra straps. I suggested boxer briefs for their tighter fit, but he preferred his usual underwear, so we went with that. He did well and didn’t even wake up (he mentioned this while on a work trip, so I couldn’t verify directly) and handled the day fine. He woke up slightly sore but simply reapplied vaseline before heading to work. He has now completed his third consecutive night. Each morning he wakes with slight soreness but feels okay as the day progresses. However, he discovered a reddish ring where the cage sits upon waking. I told him that if it hasn’t faded by the time he finishes work, he needs to take the cage off and sleep without it for the night. If the red mark persists when he wakes up later, he should stay unlocked until it clears. I think mild soreness is acceptable; from what I’ve read, getting used to night training can be tough initially. The redness worries me a bit as I don’t want to risk injury just to keep the streak going. Am I overthinking this? He edged himself three times yesterday, once right before bed (using a vibrator without unlocking). I’m hoping that ribbon might not irritate him like the elastic did if he tries it. My concern is his sleeping tight against the cage with no straps; does anyone else sleep locked comfortably without them? TD;DL See last paragraph: slight redness around the base ring after 3 nights of continuous locking, excluding a shower on day two for cleaning. No extra straps are used, just panties. He edged three times yesterday, including one before bed. How concerning is this?