So I've been working/playing with my pup. He's been great. Really happy with his personality. Very eager to learn and please. He listens well and I've spent a lot of time with him. On Saturday's me, him and my almost 10 month old human son go for a walk and play. I usually bring a bumper, a whistle and a 30' check cord but sometimes don't use them at all.
To the point...he was off the leash and he has done really well with whistle sit and come. So, while he was off walking and playing I blew the whistle to see what he'd do. I couldn't have been happier when he spun around, didn't run back and sat down. It wasn't flawless but I'm happy with his progress. I only tried it couple more times and we ended up 2 out of 3 (I got ignored on the third one). Here's a video.