she will think "what a stud". i think it is sexy when a man show his partner a little hardon bulges prior to the actual full monty.
If she's anything like me, she will want it as deep inside her as fast as possible, in every possible opening.
Unfortunately for you, showing your dick to random women and being a "shy guy" probably don't go too well together. Luckily for you, though, you've got a lot to show.