With the ability to control his emotions it wasn't that difficult to turn off the horny whenever he wanted, allowing him to focus for long periods of time. Adding to that the night he spent with Ichigo, then the wild sex he had with Nine the next day, Sam was prepared to go for months without touching his Valkyries.
Even when he invited Zero Five to bathe with him, he only intended to have a quickie before going back to the stress of his current ordeals. Unfortunately, his thoughts kept wandering to the infiltrators and the assassination attempt on Thor, leaving him incapable of setting the right mood.
Five wasn't taking it, though. It was her chance to enjoy the Doctor's company and so, she was going to do whatever it took to ignite his flames. The ponytailed Valkyrie didn't have much to worry about, though, as the man lost the will to resist the instant she grasped her destiny.