If you mean not blowing your load for few days/weeks. It does happen from time to time, whether it being intentional or not (not having time due to work or other activity).
Usually it is one week for me and by the end of the week, i will be quite horny and dont last long. The cum is alot and thick. The physical appearance of the penis is apparently bigger than usual and much more stiff according to my partner.
Sensation is very different from the frequent cum, like there are alot to unload. Easy to go for second round.