Imagine a loving couple. A sweet prey and pred.
Prey partner always wanted to get turned into cum. A steamy make out sesh turns into the prey kissing their partner's tip and teasing it.
Eventually they get head first into the shaft. It sucks them in slowly, squeezing them so tightly already. They slide into the left testicle and it immediately goes to work to digest them. Squeezing and clenching them, like tight hugs from their lover. The warmth feels like tingling and a feeling of comfort settles in their core. They giggle a little as their flesh starts to breakdown and remove itself from their body. It does hurt, but not as much as they thought it would. It's a good kind of hurt.
Their pred partner, while overwhelmed with pleasure, does mourn the fact they won't see their loved one again. But it feels too good. They take their time as they digest them. Each clench powerful but loving. They know parts of their prey partner will now be forever with them.
They pull a condom over their hard erection when they feel they're going to cum. A huge stream of cum shoots from their tip as their balls constrict to get very little drop out. The condom fills with hot creamy cum.
As they finished, the pred looks at the now filled condom. There is some remorse but their partner wanted it so. They tie a knot onto the condom so the remains of their lover won't just spill out.
With how late it was, they decided to throw it out tomorrow and went to bed. And when they came back in the morning, they see there is not just cum in the condom, their partner started to reform over night.
They were not quite themelves yet, more like a cummified version of themselves. But pred was not only relieved to see their love but excited that they could be doing this as often as they wanted.