I've seen many mishaps during this process, and all of them resulted in some $$ and bruises.
I have it down to a science pretty much, and make it as safe as possible for both of us, and the bike.
First and most important, is everyone needs to be completely geared up... helmet on, gloves on, suit comfey, all pockets zipped, etc'''
I mount the bike, and sit, ready to start off... BIKE IS NOT RUNNING...
Sidestand down, feet planted and a firm hold on both bars...
The "pre-mounting" commands are given... "ready", mount... now the communication is important, so work that part out ahead of time...
when I say "ok, get on", she grabs a "handfull" of jacket, at both shoulders (not my shoulders, but the jacket itself, and a firm handful grip at that), and holds on tightly, then puts her foot on her left peg, and pulls (not tugs) firmly and smoothly to lift herself to where she can swing her leg over (while I'm leaning forward so she doesn't whack my helmet with her face shield), then sits.. I tell her to "settle in" and when she has adjusted herself, and comfortable, she give me the "ok, I'm ready".
(This is where the "first step' I mentioned comes into play, because waiting for a glove to get put on, and dropped on the ground... or a pocket to be zipped, and a wallet or phone dropped on the ground, truly sucks... and the "WAIT" I'm not ready".. thing is only topped by the "I think I need to go the the bathroom...meme")
Then, and only then, do I release the bars, and start the bike. Once I'm comfortable with the bike running, I tell her "ok, we're off", and upright the bike (waiting for that last squirm she always does, and kick it into gear, and proceed. The "first stop", at the end of the driveway, I pay strong attention to her weight transfer, and make sure to have both feet down, and allow her to accomodate by being comfy, then we are off...
At any stop and dismount, fuel, etc., I reverse the routine, she doesn't move till I say she can... bike off, sidestand down, and again feet firmly planted, then I tell her to "get off my bike...", and Move away 5 feet so I can get off...., then I dismount.
ZERO incidences using this method, I've watched people put the bike and wife, in significant peril, buy letting them mount the bike first, on the side stand, as "you ain't gonna stop a loaded bike from falling... ain't gonna happen..."
Also letting them sit on a running bike, without you, is asking for headaches.

hope this helps, nothing more embarrassing than a drop in a gas station or parking lot, with the wife pinned under a running motorcycle..
