Buddy has a small issue, is it me?

Hi all, as you buys know I rescued buddy from Texas cattle dog rescue. He is a great dog & we are building a wonderful relationship, he has been with is since march 31 & even in this short time I already can't remember what it was like without him just thinking or talking about him makes my heart swell with joy . He really has bonded with me as well & has become my shadow . I hope I am as important to him as he is to me, I feel like I am

Anyway, we still have one obstacle, when I try to teach him a trick, even with food (anything beyond sit & down... I was trying to yeah him to play dead lol) he seems to get intimidated & goes & hides when I ask too much of him, I know it's an appeasement gesture, I just want to know why & what I'm doing wrong to make him feel that way . The last thing I want to do is make him uncomfortable. I'm not overbearing when I'm working with him, I avoid looking him dead straight in the eye & I always talk quietly to him, so what is it? Does he not trust me? I don't think it's that because when a sudden thunderstorm moves in (in tx the weather can change suddenly during this time of yr thanks to heat storms) instead of running & hiding he runs straight to me for cuddles, then I put him in thr barn office wher he can hide under the desk.

So, any insight, guys? Thanks for your time

My heeler does the same thing, mostly in agility.
I just say "oh, you okay?" in a soft, calm voice and sit down on the ground. She generally trots over for reassurance cuddles, then we back track a bit and do something easy to build confidence back up.

Just be very aware of where your dog is at with what activity you're doing and make sure you have clear criteria that isn't too big of a leap from what your dog currently can do.
Good luck.

Didn't you post this earlier in the training section?

Yeah, it is in the training section also. You should only post the same thing once as it make it confusing to have the same thing in different places.