Smooth lines drawing on oval lines

[pandawid 2]

Hi, I have such a problem that I can't make nice and smooth lines drawing with pen on oval figure. I attach a picture how it looks like....

I'd like to get nice smooth line, not like trapezium. Black stroke interrupts me in this... My goal is to make nice looking bee

[dutchshader 188]

Make the yellow stroke a little larger, than ctrl x, select the brown shape and ctrl alt v  to paste inside the brown oval