Lol. Funny answers :lol:
I think it's pretty interesting to observe what vocalists do when the guitarists does his/her lead solo (the 'her' part being an EXTREME rarity).
I find it easier to deal with that situation if i have a mic stand somehow. I pretty much know that I can just hold on to the stand, stay rooted at one spot and just look like bang my head (up and down, not on the mic stand).
I always thought that, psychologically, it's like 'hiding' behind the mic stand (the psychology of stroking the mic stand is something else, I would guess... 0.o").
But without the mic stand, that's a little tougher.