Whether in her civilian form or as Sailormoon, Usagi is very reluctant to be captured as she seriously believes that she is the most popular character to be depicted in H doujins of all time. But the good news is that her clumsiness makes it easy to catch her off guard. Even though she's concerned about her weight, she has very nicely squeezable thighs and hips so let those be the emphasis of the tie. She may get teary-eyed, but be sure to gag her before she can actually start crying. Use thick heavy gags to keep her most-effectively muffled. If her hair is loose, tie the cloth gags over it. Bonus points for using her twintails when her hair is up as part of tying her to something.