Dear Brother, i am not bothered how you or any other person does this. But i'll really appreciate if u can support your belief with LOGICAL arguments. Instead of saying k falaan bhi to aisa karta hai
Love u bro for such reply (H)
I am not the first guy to say this, u would have a better idea if u would have googled it a bit. World over seasoned detailers, teach that sealants 1st.
Now let me explain Logically, as why i say so:
- Most of the Sealants are more durable/long lasting than Carnauba waxes? Agreed??? Obviously, this is their unique proposition.
Whereas, both (sealants & Waxes) serves the same purpose, that is to protect the paint finish from alien contaminants, weather abuse, UV resistance to name a few alongwith great looks.
- They serves as a lines of defence for the paint. Thus the more durable layer of defence (Sealant) first.
3. Possible oils from Carnauba wax won't help the sealant bond onto surface, if applied over the wax.
4. Since the carnauba wax is comparatively less durable than the sealant and strips off earlier as compared to sealant, thus acts as a sacrificial layer over sealant.
Exception to the above: Water based sealants/Spray sealants can be applied over carnauba waxes because their solvent free formula alows them to bond to carnuaba waxes without compromising the protection provided by them. (e.g: dodo juice supernatural Acrylic spritz sealant)
Must read following posts:
Hi-Tech Yellow Wax#26 and NXT question
NXT Tech Wax 2.0 with Yellow #26 - Auto Geek Online Auto Detailing Forum
Auto Detailing Facts, auto detailing Tips, How to detailing Guides, how to polish, how to wax, DIY detailing, do it yourself guides
I rest my case 
Awaiting ur logical reply with supporting references, if you think i am wrong (H)
i'll suggest u to google for this. I'll let u have this blessing 