Towards the end, when the moms are hugging their sons, Vince's mom hugs him first, then begins to hug Johnny (while he says "Heyy, Ma!!"). However, in the next shot, their mother is still embracing Vince while Johnny is seen standing alone with his arms to his side joking, "Always hugs him first...I am your first born!"
Vince and Drama are supposed to be half-brothers. Earlier in the series, Drama says that Vince has his mom's legs while he has their dad's. In "Aquamom", Drama walks up to Vince's mother and says "I am your firstborn."