Usually pretty similar, though you usually produce more when you are aroused. Also, discharge could be a little whiter versus clear. It isn't a problem unless there is an odor or it's kind of clumpy.
Nope. Discharge is stuff that comes from inside, and can signal things going on in your body.
When you are aroused and get wet, its your body producing moisture to lubricate the vagina for penetration.
They are very different substances. Vaginal discharge can be made of any number of substances, but the stuff that you produce when turned on is composed of urea (found in, you guessed it, urine) and sugars that your body produces.
I think its normal for it to smell by the end of the day, I mean, everything else does, right?? Haha. Yep. Just keep it clean