Ever since the 1980s, every girl is in love with the telephone. Today it is cellulars, so back in 1990 when this episode came out, girls' love of phones was even more of a hassle. So Full House gets a common subject they must poke fun at.
DJ is now a teenager and in love with talking on the phone. To make things easier for her and the rest of the family, she asks if she can be a neighbouring babysitter to pay for it all. Her first subject is mischievous brat Brian Kagen. So aside from this episode being about a girl's superficial desire for phones, it is also a hilarious look at babysitting. Brian is a bad kid who annoys the heck out of DJ. Jimmy comes by to see how she's doing and barely anything works. When Brian sticks his head in railing bars, he can't get out. DJ doesn't know what else to do but call her dad for help, even if it means not getting her own phone line.
The subplot is the Tanner manor hosting a poker game with two of Jesse's rugged pals. They all pressure him into taking Rebecca to Graceland for Christmas instead of Nebraska. Another hilarious bit.
Every scene in this is hilarious and awesome.