Ren is a calm girl, but it's actually rather dangerous to try and take her by surprise since she knows how to use firearms and also has a lot of hidden protectors. But when it comes to being asked, she often won't have any objections so long as she isn't overly busy. She makes a good captive in her school uniform or anything with a skirt since she knows how to sway very nicely when bound. Give her a gag to emphasize her eyes and tie it either over or under her hair. Touching her spine and her sides will reveal a side to her that most people won't know exists.