Two and a Half Men - Episode 5.12 - Caregiver

Charlie invites a young woman named Mitzi over to have some quality time and as they are kissing and beginning to enjoy each other's company, she begins sneezing. Charlie gives her some nasal spray and tells her to sneeze into the pillow so he won't catch her cold. As she is leaving, she kisses his forehead then coughs right into his face. When Charlie comes down with the cold and finds himself alone at home, he tries to call Evelyn but she claims to be sick as well so she is unable to come take care of him. Later, we see Mitzi meet someone in a coffee shop and learn that it was all a setup for someone to get closer to Charlie.

Source: SpoilerFix