Chrissy Teigen -- Introduces the Vagina Raspberry ... You're Welcome, Brooklyn Decker

A seemingly drunk Chrissy Teigen just used the Internet for the greater good of humanity -- introducing the world to something she calls the "vagina raspberry."

In Chrissy's instructional video she places her face over the crotch of another S.I. swimsuit hottie ... Brooklyn Decker -- and the person shooting announces, "This is the video called vagina raspberry."

And then, Chrissy buries her face in Brooklyn's crotch and blows hard ... on Brooklyn's vagina.