Anima v2.0

(Anima can almost do it out of the box.) Do something like

reversefel, 1girl, 1boy, fellatio, on back, lying, upside-down, head back, hair hanging down

Illu V1.0

Trained in 3:4, 1:1, 4:3.

1girl, 1boy, reversefel, reverse fellatio, upside down blowjob, lying