Rapper Wiz Khalifa is reportedly stepping up his custody battle with his estranged wife Amber Rose.

The Black and Yellow hitmaker, real name Cameron Thomaz, is said to have compiled a list of reasons for his son Sebastian to be distanced from the model.

In documents obtained by Tmz.com, Khalifa alleges Rose frequently stays out all night and enlists staff to care for their son, and has "vulgar exchanges" in front of the 12 month old.

Editors at the website report the rapper plans to lodge legal papers soon and wants to recruit family members to support his case.

Rose and Khalifa split last year (14) after marrying in 2013.

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