lol, you guys are horrible!
Freak, before I ever let a passenger get on the bike, I brief the passenger on these following things, some of which have already been mentioned by other, you might want to give it a try.
1.)Passenger must keep her hands on my hips, if she's holding on to me. No shoulders
2.) Ride where she is comfortable, if that means leaning on my back, cool. If it means sitting up straight like in the picture with Eric and his wife (hot wife by the way Eric!!!), then that's cool too.
3.) She must look over the shoulder I'm turning in. Turning left, she looks over my left shoulder. This helps with the whole "lean with me" idea, just by changing where she's looking.
4.) To love the lean. A lot of passengers freak out with the whole lean thing. I usually take it easy for the first few miles, weaving back and forth in a straight line to get her used to it, then start going around corners faster and faster to lean over farther and farther. If a passenger resists the lean, and grabs a hold of you quickly in the lean, you know she's not adjusted to the whole lean thing. I usually tell her to just go with it - it feels funny at first, but learn to enjoy it, it's what motorcycling is all about - I usually also have to add that I've done this plenty times before, I know what I'm doing, and she will stay safe. She is precious cargo, and there's nothing I will do to endanger her...
5.) Once she's grown to the bike, and the lean, and is comfortable with sitting up straight (I think this is more comfortable for both riders, and looks like both riders know what they're doing to passerby), I tell her to start leaning. On a straight road, I tell her to throw her weight back and forth, and feel what the motorcycle does. At like 35-45mph, as she starts "swaying" back and forth, I then take my hands off the handlebars and point to them. She notices and is (1) surprised to learn how much influence she has over the handling of the motorcycle, (2) that the bike is still going straight even without control over the handlebars, and (3) thoroughly excited about this motorcycling thing.
After step 5, we've usually been riding for about 20 minutes or so, and have approached a sinuous track of mountain road. She's comfortable. I've taken notes about how the motorcycle is different. We can go have a blast and be safe. Before you know it, another hour and a half has passed, you're at the top of the mountian, and she's got a massive smile on her face.
A few other things to do, as some have already mentioned:
Make sure to adjust, and play with the rear suspension to find something you, as pilot, like. If the bike "bounces" too much after a bump, you need to tighten the spring. If you start feeling the rear tire getting light in turns, it's probably because the preload is too tight, and the wheel can't rebound fast enough, so loosen it up a notch or two. I prefer to run "softer" than "harder", because like you said, with a 250, it's not about the crazy speed, but the nice, comfortable, leisurely rides....
Also, make sure to check in with her at every stop light. Teach her that it's best to communicate with the visor up, and show her that you have to turn your head to the side (which means you can't watch the road), to hear her. She will realize it's about the ride, the hanging out with you, is before and after. Make her understand that if she's not comfortable, she needs to speak up, by say, jabbing you in the ribs (you know, a distinct sign, that you can easily distinguish from other signs wandering hands might be giving you

)
Hope this helps, enjoy, and be safe...
