Graboids, shriekers, ass-blasters and El Blanco

I've always hated that term for chatting up, "tuning". I guess my PC sensibilities are offended by its reductive aspect. Recently, I pondered if tuning in this sense could have been derived from importuning (~to beg to an annoying degree). While that'd make the term less reprehensible - funny even - I'm pretty sure its origin is mechanical.