As discussed with melinda, I think the trappings of historical dress easier to 'dress up'. Harder to get tone right with modern setting. I also have problems with language - I hate words like tits and dick, but can do if I change my frame of reference. So sometimes I reflect language of protagonist, even when writing third person, rather than first.

With a casual tone belying his pulsing heart and dick he asked Christine to lock the door of the outer office and she got up, wiping her tears and did so. Jonah gazed at that swaying rump. Christine looked very professional today; she was obviously trying to impress him. That tight pencil skirt ended a few discreet inches above her knee and was both business-like and sexy. She was also wearing heels – a nice change from her bloody Doc Marten’s he thought. It was amazing the footwear some of these young women wore! She’d already taken off her smart jacket so he had an unhampered view of that curvy arse as her top was tucked in showing her neat waist.
As she walked back he noticed her nicely rounded tits discreetly covered in one of those stretchy little tops she usually wore under her jacket. He suddenly realised he’d better get his act together in time with her return to his office. He refined his desk slouch by quickly clearing an edge and continuing to lean so he was half leaning and half sitting. He casually eased back so his left thigh was also on the desk with his right foot firmly on the carpet. As he thought that his raised left leg was the knee over which the delectable young Miss Miller would be bent Jonah felt another twitch in the trouser department. It was a good job he was too much of a gentleman to take advantage of the situation, he thought rather pompously as he nervously and excitedly fantasised about the secrets under Christine’s proper but sexy pinstriped skirt.
As Christine re-entered the office now less brisk than she left, Jonah found an insouciance he hadn’t known he possessed. He leaned back with folded arms and raised an eyebrow (he was proud of his ability to raise just the one but though it best not to dwell on raisings – her skirt, his dick…).
With a casualness that belied the screaming, warring feelings in his mind, heart and trousers he looked at the now stationery vision that was young Christine, unfolded his arms, gestured at his left thigh and said:
“Time for your lesson young lady. Bend over.”

I was also thinking about difference in their frames of reference and language

As the slip slowly rode up the nylon clad legs (of course stockings were impossible, he realised wistfully) he took in the delights of Christine’s shapely and rounded young thighs. He knew she was always trying to lose weight but he liked their touch of plumpness. To his delight her plumply rounded bottom seemed encase only in the sheer nylon of her pale flesh-coloured tights. He then realised she was wearing a g-string.
Once again Christine was overcome with mortification at the thought of the old scroat seeing her designer thong revealed in such humiliating circumstances.