16 month old won't wean

hello ladies, I need some opinions please. So, my 16 month old is still breastfeeding. he mostly nurses to sleep. I've tried a couple different approaches but no luck. in about 6 weeks he will be staying with his grandmother for the weekend while my husband and I go away for a wedding and I'm hoping that will help him forget about it. the problem with waiting for that is, we want to start trying for baby #2 while we are away and I'm worried that him still nursing will prevent that. So I was hoping to get him off my boob sooner. I heard that some women used vinegar to make their nipple taste bad. would I be terrible to try that? has anyone had success with trying that? I don't know what else to do. he's very attached.