While working for a previous employer one of the chaps in the office had had a mental breakdown. I was asked to take over his work as well as my own and in order to assist me his secretary was asked to work for me as well. Now she wasn't a stunner but nevertheless she was far from being unattractive. After a week or two of, what I thought was harmless flirting, completely out of the blue she mentioned men had always commented that she gave good head. Quick as a flash , and before I relised what I was saying I asked her to prove it. When she realised I wasn't joking she agreed, so I immediately took her downstairs to the male toilets and we locked ourselves in a cubicle. I invited her to undo my belt and remove my trousers and boxers which she did quickly. Then, without any hesitation she sucked my cock till I came. Now she refused to swallow, and after about 4 weeks of getting blown twice a day at work ( she would almost beg me to suck her cock) I devised a plan to get her to swallow my cum for the first time. On a particular Friday she sent me a text asking me to meet her in the toilets but I refused. I told her that by not swallowing she was only giving half a blow job and that unless she agreed to drink my cum I would not allow her to suck me again. I knew she would give in. All I had to do was bide my time. On Friday she refused. On Saturday, however, we comunicated by text and after making it clear I would not let her suck me again,it was clear to me she was getting desperate. On the Sunday she eventually agreed and I asked her to get to work early on the Monday. Monday morning arrived and I duly took her into the mens toilets and this time, I completely stripped off. What I hadn;t told her was that the last time I had cum was when she had blown me the previous Thursday. I had stored 4 days worth and my balls were swollen to gigantic proportions. She sat on the toilet and leant her head forward. I held her head in both hands and began to fuck her mouth, gently at first, but getting faster and faster, the closer I got to cumming. Eventually I couldn't hold back any more. Holding her hear tightly I pushed my cock in as far as I thought she could take and exploded for what seemed like hours down the back of her throat. It was without doubt the greatest blow job I had ever received. She carried on sucking me for about another couple of months, but nothing compared to that first time she swallowed my cum.