I have been doing some instruction in my airplane, mostly for friends and family members. In fact, I just signed my 19 year old daughter off for her tailwheel endorsement! She is the second tailwheel endorsement I have done, and was the least experienced-- basically just got her private in a 152.
Insurance wanted her to have 25 hours in the airplane, so we took our time. We also did some cross countries, and she got the signoff with something like 25.3.
A few tips: I bought a retractible pointer on Amazon. There are some times when you have to point at something in order for the student to understand. The pointer is amazingly helpful.
Flying the airplane from the back is fun. I have some biplane experience (Great Lakes) from 30 years ago, and it's not that different. In the Lakes, with a passenger, you can't see anything over the nose. You get used to it, using cues from the sides. It's really not difficult at all. I did my CFI reinstatement ride in the Citabria, which helped me to get really good at flying it from the back-- lots of practice. I put pretty much anyone I knew who had at least a private pilot certificate in the front, and we went flying.
Obviously, directional control is a big deal at the start. My daughter had flown the airplane from the rear seat some, including taxiing, and diretional control was never an issue for her. You always have to be ready to give a jab of rudder at the appropriate time, just in case. Don't ever let it get too close to the edge.
The flare was probably the most difficult thing for her to master. Balancing between hitting hard and ballooning... and then it just sort of clicked.
One area where I need to improve is in talking more and grabbing for the stick less. When the student looks like they are going to slam it on, instead of yelling "stick back!" I have a tendency to grab the stick and pull it back.
On the subject of insurance, I am specifically insured to give instruction in the airplane.