FRIENDS I know of lot of people have been upset about getting the same boring ass islands all the time, this trick WORKS.
Tried it twice in a row, got the money rock island, and then a hybrid island!!!
Get those rare islands, y'all!!!! https://twitter.com/madosaurius/status/1246741193947582464

He doesn't "blush" necessarily, I basically just use the reactiong Delight, Joy, and Encourage, and he just smiles back/repeat the reaction
I think getting him to clap along with you/express joy is the key, I did each reaction twice basically before taking off!

Make sure to talk to him first then say never mind so that he'll be looking at you!!!

Just wanted to include more results!
Island 3, 4, 5 ,and 6!
All non-native fruit trees with no hardwood trees at all, bamboo island, lots of waterfalls island, and now the 3 tiered island with several rocks up top.
Havent gotten a single one of the super standard islands at all.

So you're not gonna get like a tarantula island every single time or anything like that, but it gives way more of a chance at an uncommon island. Remember that sometimes the fish might be what's unique about the island (all garbage catches, all sharks, etc)

sorry this thread is so long, but a couple more thoughts;
1. i was wrong, he DOES blush after a while. the first 2 times i did this, he didn't get to the blushing point but it STILL worked
2. I have a theory that you can only get ultra-rare islands like the hybrid once a day!