"So you say it's for your girlfriend?"
"Um yes, it's a present..."
"We don't get many men buying bras as presents....you know the fit is very important for her comfort,,,do you know her size?"
"Yeah, she's about the same size as me..."
"So it's a present for your girlfriend who's the same size as you...is that right?"
"Okay then come with me to the changing rooms, you're simply going to have to try it on to make sure it's the right size!"
"No that's alright I'm sure it's okay..."
"You misunderstood me Dear, that wasn't a request! Maybe your girlfriend would like the matching panties and garter belt too? I'm sure she wears the same size as you there too!...Follow me Sir and we'll see what fits, I'm sure your girlfriend will appreciate it!"
"Yes thank you I'm sure she will!"