It’s been 3yrs since this last came up and the only foam tip replacements mentioned here: Is my ear misshapen? are gone.
My brand new Gen 2 AirPods Pro don’t stay in my ear with any sized ear tip.
The answer seems to be foam tips. The question is which ones work and are still sold?
I use Comply Foam for other types of earbuds. They have an AirPods Pro variant:
https://www.amazon.com/Comply-Comfortable-Canceling-Charging-Assorted/dp/B088KPNKN2/
I’d try them first. Do be aware though that foam tips are a consumable part - you’ll need to replace them every couple of months since the foam degrades.
Fantastic.
The shocking part $US20 → $44 for a consumable (https://www.amazon.ca/Comply-Comfortable-Canceling-Charging-Assorted/dp/B088KPNKN2/?th=1)
I use those foam replacements while running. The Apple stock ones were continuously falling from my ears during the exercise.
Yikes! Maybe get a friend in the US who would buy a dozen of them and ship it to you if you decide you like them? 
I don’t like these as much, but I use them for the Airpods when I’m sleeping - https://www.aliexpress.us/item/3256805620076388.html
Definitely cheaper, and might be worth a look.
On somebody’s recommendation I got the Comply foam tips and they have been great for me. They stay in better and are more comfortable for long periods. I bought the assortment first to find which fit me better then ordered a set of the correct size.
I’m the OP from that misshapen ears thread – I found that the “ear hooks” actually worked better for me than the foam tips did; I used them on my old 1st gen airpod pros primarily for running. I’d still have to adjust/re-seat my R one a few times during the run but only about 40% or so as often with the wings than without them. I stopped using foam tips after I found these; did not seem to make a difference for me with or without the wings. It is mildly annoying to have to remove/replace the wings every time you use them as the buds will not fit inside the charging case with them on, but this only takes about 5 seconds, and the ones I bought came with a handy silicone case that attaches to a keychain. I had to use a key fob to get in to my gym anyways, so these were always right at hand when I needed them.
They set of wings I bought don’t fit the 2nd gen AirPods pro but looks like they’ve released an updated version that does - here’s the Amazon link: https://a.co/d/buePJpW
I haven’t tried the new ones, I find the 2nd gen airpod pros fit slightly better for me than the old ones anyway. Hope this helps!
I too use the “ear hooks.” My AirPods Pro 2Gen will kind of stay in my ears, but not with a seal that passes Apple’s sound test. But if I’m exercising at all, they fall out. The hooks keep them in place, but again not with a seal that will pass the Apple test for sound cancelation etc. I tried foam tips, different size ear tips from Apple, just about everything else out there. The hooks aren’t a perfect solution, but they work well and are cheap as can be.
I had wondered about the ear hooks. The annoyance factor is what has kept me away so far.
This is what has made me hesitate. I purchased: Amazon.ca
In the ML size. These are a bit better than the stock ear seals. However in a sixty minute rowing session yesterday, I had to nudge them back in 5 or 6 times. (Which is way better than the official Apple ones).
Thanks for posting the product link. Those look quite interesting. I wonder how the sizing compares to Apple’s. I could see myself ordering the wrong size. 
Thanks FWIW they’re being returned to Amazon, they were a little bit painful to wear for longer periods.
