If I’m firing from retention, it’s because my opponent is within 3-4 feet of me…and most likely my left hand is in contact with them. Under that situation it’s pretty hard not to land hits COM.
Next time you’re out at the range give it a try. Walk up to the target and stop when it’s at arm’s reach or a little beyond. Draw and fire from a close retention (be sure to cant the weapon a little so it won't bind in your shirt). Use the pressure of the butt against your side to "index" the weapon. Until you’re comfortable with this technique practice by dry firing.
Once you switch to live rounds keep your weak hand pinned to your chest until you’re confident in your ability. Also, wear very good hearing protection. Since your head is either even with, or a little in front of the muzzle and only a couple of feet away, it gets very loud.

I think you’ll find it’s very easy to put metal on COM every time…all without a sighting aid.

Hey Jeremy, welcome to the forum. Nice post, well thought out and articulated. I look forward to reading more from you in the future