(located) at; (to be) in; to exist; in the middle of doing sth; (indicating an action in progress)[cedict]
他
tāㄊㄚ
he; him[cedict]
屁股
pì guㄆㄧˋ ㄍㄨ˙
buttocks; bottom; arse; end; butt[cedict]
上
shàngㄕㄤˋ
on; on top; upon; first (of two parts); previous or last (week etc); upper; higher; above; previous; to climb; to go into; above; to go up; to attend (class or university); third tone of putonghua[cedict]
撒尿
sā niàoㄙㄚ ㄋㄧㄠˋ
to pass water; to piss; to urinate; to weewee[cedict]