Avian style cloacas! Made for you harpy and anthro bird-girl needs. Put '????' and '?????' in your negative prompt for best results. Use 'penetration' for ???, and should be able to do '??? in cloaca', 'gape', and 'egg laying'.

It has somewhat of a 'from behind' bias, but can do 'on back' and 'on side' reasonably well from the front.

Seems to do pretty well for reptiles too, but as I am not well versed in the actual anatomical differences and it was only trained on avians I'm leaving the name.