It's not your imagination: after a glass of white wine or a margarita, your mouth feels drier, less fresh. It's not just a sensation, it's biochemical.
THEalcohol is a natural disinfectant, but in the mouth it unbalances the oral microbiota et decreases saliva, which plays a vital role in self-cleaning and neutralizing bacteria. As a result, odor-causing bacteria can thrive more freely, especially on the tongue and between teeth.
And since we're talking about summer, we sweat, we drink less water than we think... and the dehydration worsens dry mouth, hence halitosis.