In my book, there is a rule to conjugate verbs that are both sibilant and -ik verbs. For instance alszik conjugates in present as:
alszom, alszol, alszik, alszunk, alszotok, alszanak.
Next, it is asked to conjugate zuhanyozik. I can see that it is also a sibilant and -ik, but the conjugation is
zyhanyozom, zuhanyozol, zuhanyozik, zuhanyozunk, zuhanyoztok, zuhanyoznak
The conjugation for ti and ők are different compared to alszik. In fact, it conjugates exactly the same as találkozik. Is there a rule for how to recognize and conjugate appropriately the sibilants + ik verbs? Do I have to learn them by heart?