When you start a new game select "More than old enough." You have to answer some questions to "prove you are adult".
This is a nod to old Leisure Suit Larry games that had this same kind of questionnaire in the beginning.
To get the achievement answer four questions correctly in a row. You have unlimited retries.
Correct answers
Achievement help
This is the guide for "Old School" achievement in Leisure Suit Larry - Wet Dreams Don't Dry. At Nice Game Hints you get hints even on the achievements. Click the big button below to get your first hint on getting this achievement.