2 or 3-panel of Erza dressed as Fairy Woman and Natsu as 'Great Demon Lord Dragnnel. 1st panel, Fairy Woman riding atop Dragneel with aroused moaning, gripping his wrists. Dragneel is a little scuffed up and shirtless, scowling with a blush on his face, Fairy Woman's outfit is slightly torn in various places.
Possible In-Between: Dragnnel has broken his hands free and goes for her breasts, ripping the fabric.
2nd panel: Dragneel mounted atop of Fairy Woman from behind, one hand gripping her shoulder the other gripping her breast. Erza has an hand propped against the wall. Both are panting with smiles on their faces.
I will defer to you on how the layout is handled.
Thanks!