Gravel rash is a term used in the gay community, to describe their first anal sex experience, as often the sphincter is very tight, and may produce a rash on the tip and shaft of the erect penis.
Trent: "Man, my first anal sex with a guy gave me the biggest gravel rash on my fucken knob aye! Luckily with time, the wounds have healed and so has my gay sex life!"
by omg i am wtf uber November 07, 2006
The horribly painful rash one gets after tripping and falling, or 'pavement surfing' as it's often called.
"I fell on my face and now I have gravel rash on my face, down my arm, down my leg and on my arse"
by Skankerchank May 21, 2005