I can get an okay erection standing up but not lying down. cialis doesnt help. any fix for that?

The possibly plausible explanation is standing position increases blood flow to the pelvic area (higher hydrostatic pressure) which helps the erection. I wonder if you have any evidence or risk of peripheral vascular disease such as heavy smoking, long standing hypertension and hyperlipidemia, etc. If that is the case cialis should be more effective on standing as well.

This is unusual. Being able to get an erection means the mechanism for it is intact. drugs like cialis require sexual stimulation manipulation as well- to work. Try that in the lying down position.