The only way to smell gravity is to experince its full effect for at least 10 seconds. If it's not made up of molecules, it cannot have a smell.
Gravity is in the form of energy waves.
Well at least that's what I was taught. The smell of gravity is a subjective experience, individual to us all. So the smell of gravity is different for each one of us, but one thing is for sure. The smell of gravity, like gravity itself, must suck. You don't need any expensive doctors or anything, just a couple ounces of Arsenic.