The unusually deep aqua-blue shirt that adorns the ever so beautiful torso of Sherlock Holmes ; Alike it's cousin, The Purple Shirt of Sex, it is renowned for sending all who gaze upon it into the throes of blind lust regardless of gender or sexual orientation; a potent aphrodisiac. It received it's "bliss" name because of the visual bliss it becomes when worn by a blue-eyed Sherlock, making them a special, highlighted kind of blue.
It's first appearance is in "The Six Thatchers", the eleventh episode of BBC's "Sherlock" starring Benedict Cumberbatch and Martin Freeman.
Benedict Cumberbatch's muscles show more in the Blue Shirt of Bliss, being he'd just finished filming Doctor Strange.