Daddy is a slang term used to denote hamstrings or other largemuscle groups used in running and the term "seeing other people" denotes not firing properly but delivering the bad news in the form of a euphemism.
Damn, I came out of the gates a little bit too quick the other day during the half and well...daddy is seeing other people.
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)