The soft sign is not spelt at the end of the words after sibilants:

1. If the noun is masculin плащ, луч
2. If it is gen. pl. of feminine nouns, which end with a in the nom. sing. туч (от туча), крыш (от крыша)
3. Adverbs уж, замуж, невтерпёж

In other cases write the soft sign. Suffixes ся, те do not influence the soft sign: моешься, режьте.