The dentist pulls out a numbing needle to give the man a shot.
'No way! No needles. I hate needles' the patient says.
The dentist starts to hook up the nitrous oxide and the man objects.
"I can't do the gas thing. The thought of having the gas makes me think I'm going to suffocate!"
The dentist then asks the patient if he can take a pill.
"No objection," the patient says. "'I'm fine with pills."
The dentist returns and says, "Here's a Viagra."
The patient says, "Wow! I didn't know Viagra works as a pain killer!"
"It doesn't" says the dentist, "but it'll give you something to hold on to when I pull your tooth."