The phrase "thick jam" refers to a situation or condition where there is a lot of traffic or congestion, making it difficult to move or proceed smoothly.
Sentences with «thick jam»
After baking the fruit, they cook down into softened fruit surrounded by thick jam. (inspiredtaste.net)
A sweet, tangy, and juicy thick jam loaded with fresh blackberries and strawberries and sweetened w / a coconut sugar. (mangiablog.com)