Basically both parties of the collaboration would make one video together making sure to add plenty of funny content to attract the audience of the other youtuber. I guess it may be more of a cross promotion. Like I said in my post I don't have anything planned out because I would like both parties of the collaboration to come up with it together. They're are plenty of just plain vloggers that create collaborations together. Take Shaytards for an example he collabs all the time with other youtubers as a cross promotion.