Most often without a holster, to be honest.
I am familiar with clothing that have "holsters" built into them, if you will, as I was raised with this method of carry. Ladies and Gents had seamstresses and tailors do this, before I was born in the 50s.
Like I have said, I had some interesting mentors...
High Noon Down Under with straps at 4-4;30 is the holster I use when I do use one.
http://www.highnoonholsters.com/Product_Line/_Down_Under_Straps/_down_under_straps.html
I also have a Uncle Mike's IWB clip on, that fits a couple of niches.
The only accessories I recommend is the factory finger extension for the factory magazines, and having a gold bead for the front sight.
I also recommend having at least one mag without this "pinky" extension, as this makes the P-11 more concealable, and/or mags more concealable.
Oh, it is not a bad idea to have a holster to fit weak side, and practice weak side with the P-11.
When I lost some firearms, and firearm related items, , amongst items lost was the Down Under with straps for my weak side use.
Again, how mentored and raised to carry weak side for not only backup, also primary for some situations, it has to do with strategy and tactics.
P-11 is nothing but a plastic DA revolver that is feed through its butt.
Folks have always carried revolvers weak side, for not only back up, also for primary for S&T reasons.
Software, not Hardware.
The hardware might have changed , the software never did.
P-11 instead of a revolver...
Ain't Software wunnerful?