I was attempting to masturbate and could not make it to completion, also still very erect. any advice would be greatly appreciated, thank you.

Stick with it: Practice makes perfect. If you stopped and are still erect you may have just needed to continue. Eventually, if you stopped before ejaculating, your erect penis should become flaccid. Like the ed commercials say, if you have an erection lasting for more than 4 hours though, seek medical attention.

Priapism?: Remaining very erect can be harmful and is a medical emergency. F it does not resolve in about an hour. Priapism may be related to drug use (street "stone" or cocaine), and is usually quite painful. It also occurs with sickle cell disease. You may also have been too aggressive and have caused a penile fracture (you would see a bent penis) - and is also painful.