Place it right after the excuse in an edit, then follow it with Homer Ta Gueule for a blunt reaction, or with Zu Risiken und Nebenwirkungen to underline the medicinal joke. Keep it as the punchline in the middle of the sequence, with the reaction sound closing the bit.
About this sound
This is a short Spanish voice clip from The Simpsons, lasting under three seconds, in which a character says the line about marijuana possibly being medicinal. The delivery is dry and matter-of-fact, which makes the excuse sound both innocent and knowing at once. It lands as a cheeky, slightly awkward joke, perfect for calling out a flimsy justification without saying a word yourself.