When I updated to 1.50 before UL came out, I've never had that option. I just figured that I'll get it once I get UL. Now that I have UL, I still can't get it to show up. I tried removing all my mods,...
All you need to do is get your relationship to friend. Then use friendly actions until it says the other friend finds you "friendly" or "sociable"(either will work) and the option will show up under friendly interactions.