Guys that lonely girls, or often girls with low opinions of themselves (see also; GWLSE) pick up and go out with.
Like a McDonald's take away - it's fast, it's easy, it's cheap, convenient, and it's DIRTY. (And more often than not it's something they end up with after a night of hard drinking).
The McBoyfriends are usually ugly or plain, or have no outstanding features or personality - or sometimes no personality at all. The McBoyfriend is a tool.
'Oh yeah, I saw her last night. She was with her latest McBoyfriend.'
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)