Take it in

This lizard was doing what is know in French as 'to lizard' - it's so good when linguistics make sense, isn't it ...

lézarder⇒ (se prélasser) bask, bask in the sun, lounge
laze about, lounge about

It is a reflexive verb in the 3rd group - those ending in 'er' and as it is reflexive, it is preceded by 'se' as in 'se lézarder'.

Reflexive verbs can be found in English, a reflexive verb is a verb whose semantic agent and patient (typically represented syntactically by the subject and the direct object) are the same.

For example, the English verb to perjure is reflexive, since one can only perjure oneself, but can also be used as in 'to dress (yourself)', 'to enjoy (yourself), 'to pride oneself in one's work' etc.

In English, we simply add the appropriate pronoun compounded with the ending –'self' or –'selves' after the verb (Your / them / her / his).

There is lots more, such as transitive and intransitive verbs, verbs that change meaning when used transitively and intensive pronouns, but as you are already asleep, I will just raid your homemade-biscuit barrel ...