Achieve erection without stimulation by muscle

Is this possibe.?

Achieve erection without stimulation by muscle

I can push blood inside with my BC muscle and then hold it kind of with my IC(maybe reverse kegel) inside.(trap it)
But its not enough(or not strong enough) to achieve an erection just with muscle power.

I understand normaly an erection is achieved with the brain controlling(releasing chemicals, nerves..) it.(through visual or sensory stimulation)