A female who has a nice body, but the face of a Tijuana rat dog. Not able to look at her face, but still wanting to go rib deep on the gal, you take a lamp shade and place it atop her head, like a vet does to an wounded dog. Thus, giving her the Lampshade Lassie.
"We were all down at the bar, and this really annoying bitch with a face like Beaker from the Muppets, kept busting our balls all night. Problem is, she’s got a pretty sweet body. So we took her upstairs and all had a go at her, each one of us gave her a Lampshade Lassie from behind."
Tim - "Whoa look at that chicks ass...unreal."
Dave - "Nah buddy, she's not what you expect, wait until she turns around."
Tim - "Why, looks good to me."
Carl - "Full on Lampshade Lassie bro! I think she may have even starred in Vol. 1 of Lampshade Vixens"