Whenever you do it you will be nervous!
Took my mate out (today actualy) for his first pillion trip! I gave him a brief " tap once to let me know that you want to adjust your position" Because someone randomly bouncing around behind you is.... well an experiance. This let me prepare and brace when he did.
I did tell him to wait until we were on a straight.
More than one tap meant he wanted to stop.
If they are new to being a pillion, tell them not to lean either way. Just stay in line with the bike, until you and they are comfortable doing so. Nothing worse than someone leaning in the OPOSITE direction to the turn. Your bike will want to sit up like a begging dog!!!
A good way to show them how to lean is sit them on the back both your feet planted on the floor. Get them to lean 3-4inches over each side. Shows them they wont fall off and that the bike wont fall over! It will also show you what weight you will have to work with.
Adjust your rear spring. Really, really helps!
Pleanty of rear break as the front will get lighter and will redude the headbutting. Expect that, she will twat you a few times in the back of your bonce!
Make the first few, short trips. 10mins or so. Go to a cafe or pub sit chat, then get back on.
RELAX, ENJOY IT, ASK FOR A BLOWY! Im not sure which one is more important though!!!