To speak bullshit to someone in a complimentary way. Commonwealth "arse" spelling preferred, as this expression probably has a London origin.

Usually expressed in the negative, by someone professing sincerity.
I'm not going to blow sunshine up your arse, Peter; you're the second-best of the surviving Doctor Whos.
by Fnordicle January 15, 2008
mugGet the Blow sunshine up your arsemug.
Trump’s preferred Covid-19 cure
Vaccine? Who needs a vaccine? Blowing sunshine up your ass, that’ll get rid of that nasty corona. We have all the best sunshine here. UV, ultraviolet, you name it.
by Legitcures April 23, 2020
mugGet the Blowing sunshine up your assmug.