It can be made explicit that their goal was to get him drunk. Alternate translation: "drink wine until he gets drunk" or "get drunk with wine" (See: [[rc://en/ta/man/translate/figs-explicit]])
To "lie with" someone is a euphemism for having sexual relations with that person. Alternate translation: "we will have sexual relations with him" (See: [[rc://en/ta/man/translate/figs-euphemism]])
This speaks about giving Lot descendants as if his family were a line that they are making longer. Alternate translation: "so that we can bear children who will be our father's descendants" (See: [[rc://en/ta/man/translate/figs-metaphor]])