I understand the notion muchimi a little bit differently. In karate-based MAs, the idea of muchimi is 'continuous contact', but not in a 'sticky limbs' sense; rather, it refers to the conversion of a striking limb into a controlling limb and vice versa. So a hikite movement (conventionally labelled a 'chamber') where one of the attacker's hands is gripped and pulled back toward the defender's body to anchor and control them, while the defender's free arm delivers a pin or a strike, is followed by the striking hand becoming a gripping hand—continuing the control—while the 'chambering' fist now is recruited to deliver a follow-up strike; then it too establishes a grip, and both hands work together with the defender's pivot to throw/take down the attacker... that sort of thing. It's not the classic Taijiquan 'sticky hands' kind of thing, but just the continuous conversion of striking limb into controlling limb into striking limb... repeat as necessary. Abernethy, in his book Bunkai-Jutsu, has a nice discussion of how karate kata assume this kind of alternating use of the defender's limbs in the combat applications they encode as their hidden 'subtext'....