inflate
Explanation
This is a single-panel comic showing a clown standing on a chair in front of a classroom of students. The caption reads: "Having clowns teach Sex Ed was unorthodox, but it certainly improved retention."
The joke works on multiple levels. First, there is the absurd visual of a brightly colored clown teaching sex education, which is inherently incongruous and funny. Second, the word "retention" has a double meaning: in an educational context it means students remembering the material, but the implication is that students remember the lesson because it was so bizarre and possibly traumatic that they could never forget it. The humor also plays on the idea that school administrators are always looking for innovative ways to improve educational outcomes, taken to an absurd extreme. There may also be a subtle joke about balloon animals, a classic clown prop, being used as a visual aid for sex education.