Barairo Emperor 

Keito, a high-schooler with an odd love of plants, finds a cosplaying babe in the garden. The babe in question is Roze, the reigning King of the Plant Kingdom! Roze is on the verge of extinction due to the lack of human affection. Only sex with Keito can restore his energy reserves and as Roze's kingly gaze heats up, Keito finds himself strangely compelled. "Join with me," Roze says. Why, the audacity of royalty!