a) When a couple tries to achieve simultaneous orgasms by choreographed gyrations during fellatio.
b) The practice thereof.
"when the Cuban missile crisis is the most interesting thing to talk about, that's fuckin' Doppler, dude."
When a member of the opposite sex appears attractive from a distance, only to appear far more homely upon closer inspection. Named for the "Doppler Effect" where (for example) the pitch of an ambulance siren changes in relation to where the listener is standing when it is passing.
yo that doppler looked like a mule in a coma up close!
"Gosh shannon is such a doppler"
A female who receives oral sex, while she is defecating; the female version of a "blumpkin"
1) Frat Boy talking to other frat friends: "Dude...I blacked out last night and totally dopplered this girl I just met at the bar."
2) Slutty girl talking to other slutty friends: "So there I was on the crapper dropping this wicked dump, when in comes this retarded frat kid with a grin on his face asking if I want a doppler. He suddenly does a reverse handstand, drops his head between my thighs and goes to work. I finished dumping, of course....."