Many years ago while in Cape Town the pistol carrying boys went through a period of having such an clip attached to the slides of their carry weapon. I do recall noting it being a drill and tap job and wondering about the idea of drilling into the slide of an pistol.
The clip was it appeared, just a standard slip over belt clip used for so many applications.

Why ? It seems like an odd thing to do.

At the very least, a IWB - thin leather even - holster will alleviate the pressure points on your body.

If the attachment point is a single clip, you lose the additional adhesive retention factor between the steel and a holster, even if it's smooth leather.

The closest thing I've seen is a clip-on kydex cover for the Glock trigger. Years ago, the armchair ninjas were advocating that as a holster. I remember being brutalised on Gunsite for stating the obvious - it's just a trigger cover, not a holster.

I use that kydex trigger guard cover every day on my Glock, when I go to bed. It's developed a crack along the spine from years of use, I been meaning to get a couple more.

The belt clip on the slide - I don't get it.

On big pistols, it cannot work properly - I agree.

However, I have recently seen one on a fairly small pistol. Being very light, it looks like it could work.

My concern is how much the pistol would move around, getting uncomfortable, and possibly falling out.

A good holster is tops, I am continously searching and inspecting other ideas.

There are 'clipdraw' models, and clones thereof, for a variety of pistols including the Ruger LC9 that I have which use pin locations as mounting points. There is pretty much no way that you could persuade me to use one of these things though as a holster is a safety device as much as it is a carrier. I carry in thick hide holsters or thermoplastic ones, full stop.

In my stupider and younger days I used to sometimes mexican carry a pistol in the small of my back and I once found that the saftey had migrated to the go position. Next worst thing to mexican is holster made of a thin and deformable material like suede as it can bunch in a trigger guard. I know someone who shot himself in the backside while sliding into the seat of his beach buggy with a 38 snub in one of those soft clip on holsters.

I never knew it was called Mexican carry in small of back, carried like that from 1990 to about 2005, best carry I ever had. I still wonder if it, carrying like that was the cause of my lower spinal damage. All the years with a weapon against spine and seat, pressuring same point, back pain was the reason I stopped carrying in small of back.
I know the pro guys can proof me wrong, but it worked for me for years, but long hours driving not so much.

'Mexican' refers to carrying without a holster in the waistband rather than the position of the gun. A massive downside to small of back carry is that it's all but impossible to get your hand on the gun without it being hellish obvious.

I never knew it was called Mexican carry in small of back, carried like that from 1990 to about 2005, best carry I ever had. I still wonder if it, carrying like that was the cause of my lower spinal damage. All the years with a weapon against spine and seat, pressuring same point, back pain was the reason I stopped carrying in small of back.
I know the pro guys can proof me wrong, but it worked for me for years, but long hours driving not so much.

Paralysis from falling on a SOB carried gun is a well documented story.  You fortunately found out before the point of no return.

I have seen some back plates for Glocks, that have a clip attached.  Requires no modification and is easily converted back when you find out it is not the best idea.

Our FCA specifies the manner in which a pistol may be carried (transported).  A holster, holder or bag is specified. I do not think the clipdraw thingy falls within the specs of the FCA.

Having experienced deep pitting to the slide of my EDC, I now value a holster that keeps it well away from my skin and perspiration.

On big pistols, it cannot work properly - I agree.

However, I have recently seen one on a fairly small pistol. Being very light, it looks like it could work.

My concern is how much the pistol would move around, getting uncomfortable, and possibly falling out.

A good holster is tops, I am continously searching and inspecting other ideas.

What firearm are you specifically referring to and in which carry position would your preference be?

On big pistols, it cannot work properly - I agree.

However, I have recently seen one on a fairly small pistol. Being very light, it looks like it could work.

My concern is how much the pistol would move around, getting uncomfortable, and possibly falling out.

A good holster is tops, I am continously searching and inspecting other ideas.

What firearm are you specifically referring to and in which carry position would your preference be?

G43, S&W Shield, Star DKL etc, maybe even a mouse gun of some kind. To be carried AIWB.

On big pistols, it cannot work properly - I agree.

However, I have recently seen one on a fairly small pistol. Being very light, it looks like it could work.

My concern is how much the pistol would move around, getting uncomfortable, and possibly falling out.

A good holster is tops, I am continously searching and inspecting other ideas.

What firearm are you specifically referring to and in which carry position would your preference be?

G43, S&W Shield, Star DKL etc, maybe even a mouse gun of some kind. To be carried AIWB.

I really do like Tenicor CERTUM3
https://tenicor.com/collections/all-holsters/products/certum3-iwb-holster-for-m-p

However very difficult to obtain over here and it's pricey, I have a CERTUM3 for my Glock 19X and I've successfully carried it without a belt on shorts with a draw string, the DCC clips are a game changer for AIWB.

I might receive some hate for posting the next comment... but Armortron a local manufacturer does a very similar carry system as the PHLSTER ENIGMA but at a very better price.
You can contact him, he might have a option for you.

https://www.instagram.com/armortrongear?igsh=MTdnbDVkeTkwaW5ibg==

Bilal +27 82 747 1000

Unfortunately I don't know how to attach images.

Bilal from Armortron makes really high quality stuff. A good few people from my sports shooting club run his gear.