I realize this is probably a joke, so below is not for you, but for other folks who may be wondering what the deal is with X and Z.
They always have an X, it's a specific position. It's what Pettis played last season. It's the receiver who is always anchored to the line of scrimmage (as opposed to the one who plays off and goes in motion, that's the Z) and is normally by himself as opposed to being bunched up with the TE or other WRs. A lot of times, for right handed QBs, he's found on the left side of the line.
It was a joke, but it was also true.
Usually on the right side? Don't know if I'd say that. Obviously, it depends on the formation called. X will be lined up in twin, and trips formations, so he's no always alone. At least 7 offensive players must be on the LOS. The X is also called a split end, because he is split out, and on the end of the LOS. The Z is also called a Flanker, and he is traditionally on the TE side, and off the LOS. If a player is on the LOS, outside the TE, then the TE is covered, and not eligible to go out on a route, but you can run a play.
A Y is usually the designation for a TE. H has become a popular term for a TE who is playing in the slot, and off the LOS. Some offenses call the 4th receiver a B, or Bandit, but there are other designations...depends on the offensive system.
The main thing here is that the X plays on the LOS, so he has to be able to beat press coverage. Big and strong helps, but a quick guy can often beat press too. A Z plays off the LOS, so the defender can't line up right on him, and being off the LOS, the Z can go in motion creating more havoc on the defense, because that can change their responsibilities, and coverages right before the snap.