your trying too hard
its just saw wave mixed with some noise
comb of lowpass and highpass
some filter evelope settings
and lfo modulating the highpass filter which makes him to open and close
and i guess also automatic it manual using two fingers and twisting the knob
oh yeah and maybe some distortion
a more interesting sound will be to add a slave oscilator(adding another oscilator and syncing it to the first one...) semi tune it till it sounds right(it can never be offtune because its synced ofcouse)
and using an lfo to modulate the slave osc tune massivly.
hope this general directions will help out.
cya,Tomer.