>>11410630
>What do they eat?
I think the underlying assumption is that the girl is provided nutrients by the tentacles. There's really no other reason for a tentacle to go in her mouth, much less ejaculate there as with: >>11410520 Depending on the chemical makeup, it could easily provide enough energy to keep a woman alive and fuel the tentacles growing inside of her.
>How long before she dehydrates or starves?
The most successful parasites don't kill their host, there's an evolutionary advantage to keeping the girl alive so tentacles can be birthed in perpetuity.