Jan 26, - Three had numbness of the penis, and one reported erectile dysfunction. Only one of the men's sex partners reported a side effect: a mild burning sensation during intercourse. Emla, from AstraZeneca, is also a mixture of lidocaine and prilocaine. It comes in a cream formulation and must be used with a condom. Nov 14, - With personal lidocaine spray, anesthetized genitals are just a "please of penis-in-vagina is "adequate," while 7 to 13 minutes is "desirable.".