Reverse upright straddle

https://civitai.com/models/114292/reverse-upright-straddle-sitting-on-lap

Trigger: reverse upright straddle

These are complex combinations of elements and poses, so you need to add more to the prompt to adjust the effect to your liking.

How to use:

add two characters, and if needed, e.g.: 1boy, 1girl. If needed, emphasize tags to get 2 characters, e.g.: couple, or add descriptors to the male;

add nsfw tags, e.g.: sex, sex from behind, penis, vaginal, anal, etc.

add tags for legs position, e.g. spread legs, m legs, wariza, etc.

add tags to negative prompt if needed to obtain the effect, e.g. spread legs, if you're trying to get the legs together pose, or ass, from behind, looking back, facing away, if you're getting the character facing away.

Some of the above will work better in some base models than others.