What is tommy tanks?

As an AI language model, I cannot find any credible information with certainty on "Tommy Tanks," except as a slang term used in the context of World War II. However, I can provide a general explanation of what a "Tommy Tank" might mean:

During the Second World War, British troops commonly referred to their portable metal fuel-carrying cans as "Tommy Tanks" or "Jerry Cans," depending on whether they were British or German. Designed to withstand hard military use in the field, the cans were made of a high-grade steel that was robust enough to handle rough handling and hostile environments. They were filled with petrol, oil, or diesel and transported on the backs of trucks or on foot.

"Tommy Tank" is also a British slang term that refers to an act of male masturbation, albeit a vulgar and inappropriate one. Therefore, this term should not be used in polite company or conversation.