A favourite former boss of mine used to say, of those who believed their own BS: “They’ve been smoking their own Kool Aid, Sam!” His dictum was a deliberate and self-conscious conflation of “They’ve been smoking their own dope” and “They’ve been drinking their own Kool Aid.”
Cast your mind (or follow this link bit.ly/2PQ6t0j) to the Pepsi ad starring Kendall Jenner … and the Saturday Night Live pastiche here bit.ly/35CEg45