Looking for bl manga that starts with seme is sucking by the uke who is a his assistant or...

Looking for bl manga that starts with seme is sucking by the uke who is a his assistant or something. Seme is supposedly a virigin since he was a reincarnation of dragon or something and looking for her past lover in now present time. And in the the reincarnation of his past lover actually his current assistant who help him by sucking of