Learn Turkish: Ne zaman makyaj yapıyorsun? - When do you do your makeup?

In Turkish, it is very common to drop possessives and reflexive pronouns when the context makes it obvious. Since putting on makeup is generally an action you do to yourself, just saying makyaj yapıyorsun (literally "you are making makeup") is perfectly clear. Adding a word for "your" isn't necessary unless you want to add special emphasis.

If I wanted to emphasize "your own makeup" using the reflexive word kendi, how would the sentence change?

You would say Ne zaman kendi makyajını yapıyorsun? By adding kendi (own/self), the word makeup becomes a specific, possessed object. Because of this, it needs the possessive suffix and the specific object marker (accusative case), changing makyaj into makyajını.

The translation says "When do you do", but yapıyorsun is present continuous ("are you doing"). Why didn't we use a simple present tense?

In Turkish, the present continuous tense (using the -ıyor suffix) is very frequently used for general habits and routines, not just actions happening right this second. While Turkish has a specific tense for general facts, using -ıyor for everyday routines is completely natural and standard.

Do you always use yapmak (to do/make) for putting on makeup?