First off, I'm not a 6 plus user. But I have the same issue occasionally. I use my pinky to support the bottom of the phone. I've done this with every phone I've had. Incredible, GSIII, Z10, iPhone 4s,5,5c, HTC M8, and my Moto X.
Currently I have the Moto X and it's pretty comfortable, but it's thicker, curved and smaller than the 6 plus. The iPhone 4s is pretty weighty and it will make my pinky sore after prolonged use, but it isn't near as large, just heavy.
So yes, you're not alone!
I also have a visual representation, curtesy of the iPhone 4s
Basically the weight rests on the pinky. I can wrap my hand around the side, but that makes it much more difficult to use.
Size comparison.
Currently I have the Moto X and it's pretty comfortable, but it's thicker, curved and smaller than the 6 plus. The iPhone 4s is pretty weighty and it will make my pinky sore after prolonged use, but it isn't near as large, just heavy.
So yes, you're not alone!
I also have a visual representation, curtesy of the iPhone 4s

Basically the weight rests on the pinky. I can wrap my hand around the side, but that makes it much more difficult to use.
Size comparison.
