It didn't look like it at first but I think the flower and mantis imagery, along with the line where she says she wants his flesh, blood and "dna" does seem to imply sex was involved.
Characters seem to be a bit unbelievable. The dude has the personality of stale bread and his primary trait is being clueless about things. Fuyuki is way too outgoing to be spending most of her time with this guy, and no way a cute rich girl like Akino would have this much trouble making 2...
Doesn't do so well as a cooking manga because the ingredients is of another world hence difficult to relate to. So far the Isekai aspect is pretty lacklustre due to the story taking place exclusively with the tribesmen, and taking way too long to wrap up.