Unless you have a complete death wish, do NOT attempt to take KOS-MOS by force or even off guard as her sensors allow her to detect oncoming people. She is, however, fairly easily befriended by those she does not consider a threat and will allow herself to be bound for fun. Despite being an android she does have very fair skin and securing her in a position that leaves her butt viewable and accessible is the best bet as it is as squeezable as it looks with how nicely she swings it when walking. Her bonds need to be heavy if she's to be kept for long periods. As for her gag, use anything that will not get in the way of her long hair.