Obligatory 'long time reader first time poster' comment. I'm relatively new to RP forums. Yet to post my 'shit' by way of introduction. I know a big part is that I'm still clinging onto my ego. I'm Learning to own my shit, reading, learning to lift finding my mission etc. but RP at least has me on the right path.

Now to my question: I have seen the acronym DEER used a few times. Haven't come across it in my readings and can't find it in the 'terms and acronyms' lists. Can anyone tell me what it is please?

Edit: Answered below. Thanks. Leaving this just in case any one else is wondering.