How to define a cone or other add on shape as a support in PrusaSlicer  

How to define a cone or other add on shape as a support in PrusaSlicer

Forgive me if covered and I did not find.

I am printing a 1 cm diameter X 10 cm long cylinder using PLA and Prusa printer. I printed the first one vertically perfectly.

Beginners luck..... Ever after about 8-9 cm into the print the cylinder wobbles a bit and a rats nest ensues.

I have used a brim and the Prusa included glue  and Amazon suggested Magigoo to adhere the vertical cylinder to the print plate but still it wobbles and fails.

Next in PrusaSlicer I added a cone 3 cm high to the cylinder stl file: this would obviously keep it from tilting and printed fine, but the cone is solid to the cylinder it surrounds.

My question: how in prusa slicer can I have the cone be defined as a support: i.e."porous" and break away able.

PHOTO BELOW:

left successful print with a cone at base but solid cant peel away

on the right the failed cylinder about 70% done.

Still not sure why it worked once perfectly.

I printed the cylinder on its side with supports: but the roughness from the support peel away may the cylinder which is an axle in the finished product, not glide smoothly like the successful vertical print cylinder.

TY for reviewing my question.