ACD - Austronesian Comparative Dictionary Online

*waŋkaŋ spread the legs apart

WMP
Bontok	wákaŋ	to stride, walk with large steps
Ifugaw	wákaŋ	great steps in walking
Javanese	onkaŋ	sit with feet dangling
CMP
Manggarai	waŋgaŋ	walk with the legs wide apart; lie on back with legs spread open while sleeping
Bimanese	waŋga	thigh

With root *-kaŋ₁ ‘spread apart, as the legs’. Amis wakaŋ ‘lie on one's back’ may be related.