The butt resting on a surface (often a piece of furniture for the purpose, such as a chair, couch, or bench), possibly in addition to the legs or feet. For a position with the knees on the floor use kneeling (except with seiza below).
Specific types of sitting:
- Rump on legs, both legs below body: seiza
- Rump on floor, legs bent back on either side: wariza
- Rump on floor, legs both to the same side: yokozuwari
- Rump on floor, knees splayed, soles of feet joined together: butterfly_sitting
- Rump on floor or on seat, legs crossed in front:
source: danbooru wiki