my gf and i have been goin out for a year now and we havent really had sex yet.. she and i both kinda decided we would wait till marriage or wait till we know we are ready. shes had a few partners before and i have had none. i dont have any problems gettin my guy up when i get head or hand job etc.. but some times my girl is really into it and she wants me to put my penis inside her and i guess just mess around or whatever.. i dont know what it is.. i guess i think about it then or something and after getting inside her pussy my penis goes down or basically i go down before i go inside of her.. there were times she has gotten mad.. and times where i kinda knew she wanted to turn me on so we could kinda have sex and i could tell she was fustrated.. i think the main thing is i think about it cuz i havent really done it before and we dont use a condom and i dont know how far she wants to go with it etc.. and i have noticed that i think my penis goin down when im bout to get inside of her.. anyone know what i shoudl do or have any advice? do those herbal medicines work? to help keep an erection etc?