Conversation dwindling out was a sticking point of mine and seems to be worst when I'm a bit drunk. The way I got over it was, having a random question in stock that I know I can work around. I tend to use "do you like giraffes?" said quite slowly with curiosity. From that I can do a really bad giraffe impression, talk about how much I like them with their big long necks, talk about the potential of giraffe racing and how we should set up a league together and how cool it would be, imagine if they had short necks or if a zebra had a giraffe neck, neg them by saying you remind of a giraffe, but don't worry I love giraffes, arrange a pretend date to a zoo or to Africa, the list goes on. Once the mood of the conversation changes to a bit silly it's a lot easier to come up with random crap to talk about and be entertaining. I tested it on girl mates I'm not into first just to get a feel for the conversations that could come out of it and have it as a reference point but you use pretty much anything you want.