Well is there anything i can eat or something i can do mentally that will help me maintain erection for a long time?
How to maintain erection?
Don't think there is really miracle cure for what you are looking for but eating healthy and exercising helps the body.
One nice thing about working out it helps to release more testosterone into the body, and because of this you can notice an increase in your libido which might increase arouse state.
"Don't be a Dork! Wrap your Pork!"