Momiji is an incredibly sweet gal but she isn't stupid. If she senses that you're trying to befriend her for the sake of just tying her up, she won't fall for it. And catching her by force can be tricky due to how elusive she can be so it's best to genuinely earn her trust or knock her out first. Bind her in a shibari that emphasizes her curves and leaves her hips accessible for the most fun with her. Any gag that highlights her eyes will look good on her.