Pyjama Shark

Whether consciously aware of it or not, the pyjama shark is a metaphor or euphemism for an errant erect penis, escaping the unbuttoned cave of non-fastened pyjama crotches.
ALT: Of a person; someone who cruises hospital wards for sex.

1: ...and his pyjama shark was leaning out to see....
2: “That guy’ with the chocolates and flowers is a disgusting pyjama shark...”