Marowak works on a spectrum of teams. He plays a little differently depending on what surrounds him though. Defensive teams are generally going to be cagier about switching him in, set up more often when he does come in, and are more likely to forego coverage for Rest + Heal Bell shenanigans. Offensive teams are going to switch him in more often as A) they prioritize maintaining constant pressure, which Marowak applies a lot of, and B) they often don't have a Raikou to bring in on Thunders; they'll also be more likely to attack rather than set up, and are more likely to run Hidden Power for coverage or, much more rarely, forego Swords Dance for Rest + Sleep Talk (or perhaps a fourth coverage move like Fire Blast for hitting Skarms on the switch!)
That said, you want to mix up your balance between setup and attack, switching in and staying out no matter what your team. Using a stall, you might want to be a little looser with Wak than your comfort zone dictates in order to make progress; Rest + Heal Bell often enables this. Using an offense, you might want to be a bit more conservative and use him more as a threat to do things like prevent Ttar from switching in fearing the double-switch (many offenses can struggle a bit with Ttar), or prevent Electrics from going for Thunders, thereby allowing Lax more chances to switch in.