That's so awesome! I don't know why, but it's so delightful to introduce another child to the concept of slinging. I was babysitting a 16-month-old girl a few months back for about a month who had never been in a sling. Ds was in a phase where he only wanted to ride in the stroller or walk, so when we went out, I decided to try her on my back. She loved it. After a few days, she decided that her signal for wanting to go outside would be to come and try to climb on my back. :LOL
Have fun!