tibloc Using Tibloc and Prusik to climb

[MastJack]

I am trying climbing for the first time using a Tibloc attached to foot loops, and a Prusik attached to the harness on a second rope for safety. Both ropes are taut. The Tibloc works faultlessly as does the 3-wind Prusik. The idea is I stand in the foot loop with the Tibloc holding my weight. Then I raise the Prusik on the other rope, let that support my weight, and rise the Tibloc again to stand on, rinse and repeat. It all sounds simple.

But the instant I go to stand in the loop with the Prusik ready to raise, I swing away til I am almost lying back. despite the ropes being tensioned the swing is enough that I can barely hold on to the rope let alone raise the Prusik. It takes significant effort just to stay anywhere near recumbent let alone upright. 
I decided to try it on one rope, with the Prusik above the Tibloc. Same problem though. I am so busy grasping the line to stay somewhere near level, that I can't raise the Prusik to help me out or the Tibloc to take another step. 
Both Prusik and Tibloc are  working fine, it's just my feet swinging away from me and me almost laying back horizontal that causes the problem.
Where am I going wrong?

[Brocky]

You need to switch your weight, or center of gravity from the Prusik rope to the footloop rope when standing up. Hanging on the hitch rope while trying to stand up on the other rope causes your feet to swing out from under you.  

Another option is to use one rope, hitch above the Tibloc.

[MastJack]

Thanks. I ditched the Tibloc as it slipped and ripped the casing of a rope so I now have two ascenders. Same problem though, I can't stay upright. 
Maybe my balance is just appalling lol. 

[Steve Bullman]

Good call ditching the tibloc. It used to be classed as a rescue ascender for the very reason it shreds ropes 

[Dan Maynard]

It sounds like you're trying to climb for the first time by inventing a new method of climbing. Why not start with the rope double over a fork and back to a prussic in conventional Drt, and then use a foot ascender to push you up?

[wood cutter]

tibloc is mainly used for emergencies only