Species, shmecies!

Trollia notices immediately as your disguise fails and you revert back to an elf.

"What the...!" She exclaims.

Remollie also exclaims, but for another reason:

"OH!!! It just grew! AAAHHH!!!" she shouts as your dick reverts back to it's normal elf size as well, which happens to be much bigger (since elves are larger than nymphs in every other respect).

From the combination of Trollia blocking Remollie's vision of you and the intense pleasure she's getting from an expanding cock just after orgasm, she doesn't notice what you've become, and gets exceptionally horny from it. She wildly grasps Trollia's rear and jams her face in her mate's slick pussy.

This happens to be the reason that Trollia wanted Remollie as a mate and it gets her off like nothing else. She shuts her eyes and concentrates on Remollie's attentions and effectively forgets about you!

Also, luckily for you the change and writhing carnal pleasures you're witnessing in front of you have given you a second wind...