It is the basics of prone masturbation. One does have to take care as the pressure build up can cause the man to require more pressure to orgasm.
Now if you are a two bum chum :) i.e. quick on the trigger this is a good way to help learn delay.
I spent time researching this (I have real shit reason for why I orgasmed this way (PIV and this not important). But what ends up happening is there are three main zones for a guy's orgasms.
The head to shaft, the base of the penis and the prostate.
When you prone masturbate, you are applying pressure to the first two zones, and any prostate orgasm is mind blowing. So you are getting a taste of the p-spot. The other fun thing is ... doing so allows you to masturbate more often since the release is different.
So congratulations on finding this ... it is wicked fun but do be careful, since in actuality <10% of men orgasm this way.
But it is a fantastic way to orgasm.
As for the mental things ... oh yeah. In my closet of fun, I have lots of things to choose from to get off. So it is like spinning a wheel and says what shall we cum to today .... :)