Unfortunately, French is a language with many exceptions to the rule. However, one example whereby you can guarantee that  no exceptions occur is the following:

No matter which tense you are using, no matter how complicated or simple your sentence is, when using reflexive verbs, for example, se doucher, se relaxer, s’amuser, se laver, the reflexive pronoun must ALWAYS reflect the subject of the sentence.

Reflexive pronouns are:-

me 

te

se

nous

vous 

se

Let’s look closely at some examples.

1. Je me douche tous les jours

2. Tu vas te relaxer en vacances

3. Il s’amusera en Italie 

4. Nous nous attendions à ce que les enfants arrivent à 8 heures 

5. Est-ce que vous voulez vous relaxer cet après-midi?

6. Ils s’y seraient lavés