A few things:
1. A sissy should eat her own cum. This is a given, something taken for granted, no? It doesn't matter the method or place of orgasm (a blow job, fucking a woman, a hand job, jerking off onto a woman's feet, whatever), sissy cum should, no, must, be cleaned up and recycled.
2. Many sissies don't want to eat their own cum. Oh, they do BEFORE them cum, then, suddenly, right when they do, they lose all interest. This is a bad thing.
3. One solution? Prostate milking, of course. This works particularly well with those sissies who find themselves in chastity, as a proper milking produces a weak, almost non-orgasmic release of cum, and more important, does so without that dreaded loss of libido that makes eating cum so difficult for most sissies.
4. What about a sissy who just simply refuses to lick up ever drop? There are clinics for that: