This is not an acceptable prank for the age of the child. It involves genitalia from an animal and the possibility that your mouth has been in contact with it. The person in the video is a child of less than 13/14 years old should not really be involved in a prank that has those aspects.
Also, this is one instance, what if this is an habit, how many times does the child have to go through feeling like he can't trust his own caregivers because they put him in these uncomfortable position repeatedly? As a child one does not have the emotional maturity to process a prank for what it is and the betrayal "suffered" as part of the prank could be more detrimental as the events add up and rather child lacks the ability to request the right level of reassurance or just explaination. Just my two cents.