We began riding two up on the GTS 250 about two weeks ago, and only less than six months into riding full-time, we love it!
I am much much bigger than she is ... wider, slightly taller ... she is long and slim. The first day out was a practice run in the neighborhood (not a lot of traffic, side streets, so on) ... Keeping the throttle very steady and on our straight away, she clung to me like we were heading into a haunted house.
The second and third time found me increasing the speed and taking us out for a "longer" ride -- meaning, more than 15 minutes.
We discussed risks and that no matter what, no questions asked, if she were to feel uncomfortable or unsafe at any time, she'd be empowered to tell me to stop, and ... no questions asked, I'd rearrange. As a newer full-timer I am not much of a risk taker, but to get the bike up to 50 might feel for her like 120 ...
After our first three days she found "her spot" on the bike. She knows where and when to hold and learned fast to enjoy the scenery.
We are coming off a four day weekend and have likely driven more than 100 miles in three days, and ... as the weekend began (on Wednesday night), we went and bought a communication system for the helmets. I cannot tell you how much more fun and enjoyable it is to be able to talk normally and hear what we're saying and experiencing ...
For me: My shoulders and lower back are sore. I was as nervous as her the first three days and my body reacted to those nerves. Two weeks in and last night we went for a late night ride for ... um ... carrot cake and coffee. A 5 minute spin in the area took us about 45 minutes ... why? Because it was a gorgeous night in Pasadena and we didn't want to get off the bike. It was a wonderful and romantic little date and on the way home we sang 80's tunes, out of tune until we got the bike parked.
Advice: Go slow. Don't take risks alone. What you think you can handle, your partner may not -- be mindful and respectful. Check in when you are tired. If you don't think you can handle the ride, you likely can't ... rest it out. Go places you'd been that you're just dying to share with your partner, get your camera/ phone ready.
Advice: If you aren't already in love and don't want to be, consider remaining solo