I usually use a 2nd person but if I'm doing solo, I put the reel on a little 4'5" no name jig stick I've had since a kid and sit the spool on a shitty old towel with a screw driver through the hole and apply pressure with my feet.
And David is right. You will sweat! And doing it my way solo, your legs burn as well as your arms. While I was young, stupid and unsure of how much line I only needed, I once put 1 kilometre of 50lb braid on a TLD25 by myself. Worst decision ever!