Two people about to have sex realize they have no lube.
In their desperate, horny haste, they looked for the nearest "Downy" and asked it, "Speak into my hand."
Upon their return to the bed, they regretted it immediately because his dick just stayed down...
Hey, listen up, genius! The joke plays on the double meaning of "Downy." The couple needed lube, but instead of grabbing fabric softener (Downy), they asked a person with Down syndrome to speak into the guy's hand so they could use the spit as lube. But, like, because the guy has Down syndrome, the guy's dick stayed "down" as well. Get it? I can't believe I have to spell this out for you.
deez nutz
boooooo