I've done it before if I'm in the bath soaking after a long mma training session and my body is aching. But most of the times I have a towel that is long enough that I can reach the back of my neck and hold it by one had while applying pressure with the other hand. I wish I had a barber chair :P lol.
"The world ain't all sunshine and rainbows. It is a very mean and nasty place. It will beat you to your knees and keep you there permanently if you let it. You, me or nobody is going to hit as hard as life. But it ain't about how hard you hit, it is about how hard you can get hit and keep moving forward, how much can you take and keep moving forward. That's how winning is done!" ~Rocky Balboa