sich ausziehen

Since it is reflexive, you must use the pronoun mich, dich, or sich. The prefix aus- is separable. In a normal sentence, it jumps to the very end. You say: Ich ziehe mich aus. If you are helping a child, you say: Zieh dich bitte aus. It sounds a bit like a puzzle, but it becomes second nature quickly.

Use it whenever clothes are coming off. It is perfect for the doctor's office. It is essential for the locker room at the pool. You will use it at home before a shower. It is the standard, neutral term for the act of undressing. No one will find it strange or rude in the right context.

Do not use it if you are only removing one item. If you just take off a hat, use abnehmen. If you take off a coat, use ausziehen without the sich if you mention the item. For example: Ich ziehe die Jacke aus. Using sich implies the whole outfit is going. Also, avoid shouting it in public unless you want some very confused stares!

Germans are generally quite relaxed about nudity in specific places. Think of saunas or FKK (Free Body Culture) beaches. In these spots, sich ausziehen is just a functional step. There is less 'shame' attached to the word than in some other cultures. It is a practical part of the daily routine. It is not inherently sexual; it is just biology and laundry.

If you want to be more formal, you might hear sich entkleiden. That sounds like something from a 19th-century novel. For shoes, you just say die Schuhe ausziehen. If you are changing clothes, use sich umziehen. If you are putting clothes on, use sich anziehen. These 'pull' verbs are a big family in German!