Beneath the Valley of the Ultra-Vixens

The movie starts with introductions to the people of Small Town, USA. Among them are the huge breasted evangelical radio preacher Eufaula Roop (Ann Marie) who mounts Martin Bormann inside a coffin; a salesman who gives oral pleasure to a large breasted housewife (Candy Samples); and the very large African American Junkyard Sal (June Mack) who sleeps with her working class employees. Finally, there is Lamar, who anally rapes his large breasted wife Lavonia (Kitten Natividad) after she tries having vaginal sex. Afterwards, she kicks him in the groin.
While Lamar heads off to his junkyard work, Lavonia spots a young man skinny dipping in a lake. She sneaks off and undresses, then jumps the boy from behind and proceeds to mount and rape him. The young man soon escapes, but she dives down, catches him underwater by giving him oral sex and then overpowers him. After he succumbs to her, she learns his name is Rhett and that he is fourteen. Later on, the aforementioned salesman comes to her home and she ends up having sex with him, too.
Meanwhile, Lamar, who previously turned down Junkyard Sal's invitation for sex, gets called to her office where she meets him in her underwear. She locks him inside and threatens to fire him if he does not succumb to her. Lamar, who we are told needs money for correspondent school, lies down on her bed. She forces herself on him in numerous sexual positions. After a while, she lets Lamar have anal sex with her and gives in when a suddenly enthusiastic Lamar stops her from continuing into other positions. Lamar then spots fellow employees peeping from the window. He breaks open the door and beats them up. Junkyard Sal then fires the peepers and Lamar for being "perverts".
Lamar goes to a bar, where Lavonia masks herself as Mexican stripper Lola Langusta and drugs his drink. In a motel room, Lavonia rapes the unconscious Lamar â by first triggering an erection via oral sex and then by finally having vaginal sex with him using a sock as protection. She frees him to test if she changed his ways, but he runs away. Back home, Lavonia has sex with a truck driver. As she checks the clock smiling, Lamar returns. A fight ensues and Lavonia helps Lamar by burning the truck driver's scrotum with a light bulb.
Lamar takes Lavonia and himself into dentist/marriage counselor Asa Lavender (Robert Pearson). After the dentist takes Lavonia to the dental room, his nurse kisses Lamar. As the dentist hurts Lavonia's teeth and she counters by grabbing his crotch painfully, Lamar rapes the nurse. The doctor then switches places with the nurse. When seeing Lamar still has his pants down, the doctor tries to rape him, but Lamar hides in the closet. While the nurse and Lavonia have sex using the nurse's double-ended dildo, the doctor uses various weapons to force Lamar out of the closet. Lamar eventually beats the doctor up and interrupts Lavonia and the nurse. An arrangement of Stranger in Paradise is played in the background throughout the dentist scene.
Lamar decides his cure lies in faith. After dropping him off at the radio station (a power station), Lavonia goes home and has sex once again with the truck driver. Lamar takes his pants off in front of Eufaula Roop's booth and reveals an erection. She immediately goes off the air. When Lamar tells her he wants to be saved, she sends him to her cleansing room (a bathroom) while she changes clothes. Lamar lies inside a water filled bathtub as a robe wearing Eufaula Roop stands above him and baptizes (and almost drowns) him. Suddenly she takes her robe off, sits down on him and rapes him, all the while preaching to her listeners about his salvation. Lamar heads off home, punches the truck driver and has sex with Lavonia.
After Eufaula Roop leans back on her chair and moans, the teenager Rhett climbs from under her desk and she takes him to the bathtub.
The narrator heads off to his own home, where the teenager Rhett, his son, has sex with the narrator's huge breasted younger Austrian wife, SuperSoul (Uschi Digard).

Question: What do Lavonia and Lamar use to burn the truck driver's scrotum?
Answer: Light bulb