Side to side motion on a bike going up hills

[Fnaar]

I did a nice long and hilly ride yesterday, and when I was 'in the zone' and honking up hills, two things occurred to me:
1) If sitting, I sometimes (on the hardest bits of the hills) move my upper body side to side.
2) If standing, I sometimes move the bike from side to side underneath me.

Questions:
1) Why is it that either of these side to side motions makes the uphill struggle feel easier?
2) Is it an inefficient way of cycling? I would assume so, but I don't understand what principles are behind this.
Any ideas folks?

 

[Peter Armstrong]

Id like to know this too, When going uphill, stood up, I push on one side of the handle bar and pull on the other, then the opposite way, like a snake goin up a hill.

 

[MrJamie]

According to the hill climbing video in the other thread, it lets you use upper body strength to put additional power into the pedals, kinda pulling the bike against your leg stroke with your upper body, but that its less efficient and will burn you out if you do it for long, although it lets you stretch and use different muscles. Seems to make sense

 

[Smokin Joe]

You lot have too much time on your hands.

 

[snorri]

You stand on the pedals?