I am  looking for dramas with +18, mature content with passionate kisses and erotic scenes. Thank you for your help!

I'm not sure about dramas, but there are Chinese movies with erotic scenes.

Lust, Caution

Summer Palace

There are very few Chinese movies with sex scenes because if there's too much sex, it gets banned in China.  Both of these movies were banned.

If you just want kiss scenes but not sex, you'll probably be able to find those.

Sealed With A Kiss - highly eroticisized push/pull relationship, quasi DOM/sub relationship between leads, lots of forced seductions & passionate kissing. For mature audiences only.

Too Late To Say I Love You - romantic, fire burning passionate kissing & love making. I have yet to watch any drama that tops the physical intimacy in TLTSILY! I loved it, highly recommend! Wallace Chung was an intoxicated man in this drama ... intoxicated by the fl. ;)