Its a Freudian classification systemn which divided people (quite erroneously) as "oral" or "anal". Anal fixations are concentrated on controlling outflow, obviously, and the retentive subdivision is, as mentioned, very reluctant to allow outflow -- extremely picky about details and even when something is perfect only sending it out into the world withthe greatest reluctance. I suppose there is an opposite obsession which is more diarrheoeic in nature -- outflow at any cost.

I am not sure what an oral retentive would be -- perhaps not allowing things into their space readily, as contrasted with suckjing up everything in sight. But I don't remember my Freud that well -- been too many years to hang on to a marginally useful model!

A