Wikipedia can help with the first, which is an interesting concoction which sounds like hard work (https://en.wikipedia.org/wiki/Flip_(cocktail) : " a mixture of beer, rum, and sugar, heated with a red-hot iron ("Thus we live at sea; eat biscuit, and drink flip"). The iron caused the drink to froth, and this frothing (or "flipping") engendered the name. Over time, eggs were added and the proportion of sugar increased, the beer was eliminated, and the drink ceased to be served hot."), but 'slings' WP entry is rather vague, and while I can find various combinations of pepper and rum in Google, I'm not sure any of them are what is meant.