A Low Guttural Tongue-Flapping Noise

S2 E19: While at a coffee shop, Alan and Charlie encounter Sherri (recurring guest star Jeri Ryan - "Boston Public"), a woman who once dated Charlie just so she could have sex with him. Alan is enchanted with her beauty, so Charlie encourages Alan to ignore his memories of teenage rejection and ask her on a date. Alan's befuddled approach is surprisingly successful because Sherri no longer wants shallow, purely sexual relationships and is hoping to experience a deeper, more caring connection. Unfortunately, during his date with Sherri, Alan can't seem to get thoughts of Charlie with Sherri off his mind.