Well, it is a classic - both for secretary sex and for them personally! Both the desk and the suit and tie - and the 'sir' which, yes, it's been a long time since he's heard that and it sends shivers of unexpected lust through him and an appreciative smirk spreading across his face.
"I'm glad you think so," he purrs, coming off the desk and forward a step or two before reaching out to take a hold of the just-straightened tie and using it to pull Ianto forward right into his personal space, eyes tight on his from a distance of about two inches.
"I suggest you lose the trousers, Mr Jones, if you don't want them torn apart so I can get to what's mine."