Mostly, clankin' tankards just means getting sloshed - most likely in a medieval setting. However, the phrase could absolutely be a euphemism for something (like getting railed in a sundress by an Hobgoblin, or getting boofed by a Bugbear).
"Avast ye! Hast thou been Clankin' Tankards at the Gasping Gander?? I can see the juicesall overyer face!"
When one journies into an area that could've been explored by any man yet was previously unexplored because no man was stupid enough to do so. Typically used to describe how a fat girl loses her virginity.
"Jim I heard you took fatty Patty's virginity at the dance last night?"
"Ah man word about that got out? Yea everyone told me not to but I went Louis and Clarking"