Manllow was apparently coined by self-described “art geek and fashion freak” Lala Liu, whose Manllows shop on Etsy defines a Manllow as “half man half pillow.” The copy goes on to describe Mannlows as “[t]he greatest gift of all time. 105% creepy, 5% loveable [sic] or 105% loveable, 5% creepy. You pick.”
A less-awkward spelling would have been Manillow, but it’s possible Ms. Liu was concerned about legal action from the artist formerly known as Barry Alan Pincus.
Depicted above is the Edward Cullen Manllow (sold out, alas), named for the vampire protagonist of the wildly successful Twilight series, as portrayed by actor Robert Pattison. (This particular example might have more appropriately been named a Vampillow.)