To sleep together in the same bed or similar space. Does not imply having sex. It's what "sleep together" would've meant if we hadn't turned it into a slang idiom meaning "to have sex".
"The kids used to cosominate until we got them separate beds when they were 6 and 8."
"You can crash here if you don't mind cosominating. I don't have a spare mattress."
"We just started having sex last week, but we've been cosominating for months."
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)