This may be true.
It began shortly after his littermate, Hanna, died. I was determined to spoil him rotten. Even after two more mice, females named Belle and Pudding, were brought in, I still focused my attention on Mabel. And then one day after picking him up and expecting him to do his usual fussing about, he just tucked in his paws and tail and sat in the palm of my hand, looking up at me with mousey goo-goo eyes. From then on I figured that we were buddies.
Mabel and I have a routine of sitting together in the morning, afternoon and evenings. I attend to his food needs, check to see if anything in his cage needs to be changed, and then I pick him up. Mabel will fuss a few seconds, especially if I have handled any of the other mice before him, checking out my fingers and sniffing up in my face or even touching his nose to mine if he his close enough. And then he will settle in, tucking his limbs in and letting his tail relax.
Originally when we did this he would more or less take a dump in my hand while sitting there and appear to think nothing off it. But, one time I found him trying to roll the dung off my hand with his nose. And there have been a few times when I noticed he does what I refer to as "projectile pooping." That is, he will literally set his back end off the edge of my hand and then with a quick twitch send it flying. Now I have noticed is he "really has to go" he will get all twitchy, even chirping at me, as if it were a warning. That I when put him back in his cage so he can do his duty.
Alas, the girl mouse who turned out to be a boy has had a good life so far.