One very good way to get temporary larger head is to get a good dick sucker that works on the head only. It makes mine larger.
I have tried the jelqing and it makes the flaccid dick longer but my head never gets bogger than the shaft.
A very effective method, again for temporary head size increase, is to use one of many electric pumps. The hand pumps will not do it. I have an electric vacuum pump from Dr. Kaplan. You can find his website and get prices. I first use an approximate 9 inch inside length tube that is advertised as to fit most penis sizes--not necessarily true. When I first started using it, my 8 or so inches would fill the length and girth of the tube, but after 30 or 40 minutes, my penis could not expand any more and was at the full 9 inches. I then bought another tube much larger in diameter and 12 or so inches long. I use the first one and fill it and then switch to the larger one. With the larger diameter, the length does not expand much more, but the girth expands tremendously. My head is normally the same size as my shaft and I am uncut. The longer I use the larger one, the bigger my head and body girths get, with the head larger. The head stays larger than normal for a day or so after pumping like this. After doing this a number of times, there is noticeable thickness and the first tube will fill thickness wise faster and my length will never get to 9. Then I have to shift to the larger tube, again over time making it even thicker.
The end result has been with two women that fucking with normal size dick they were conditioned to get, then pump in this manner, and both would nearly pass out with the increased thickness. They liked it that way occastionally but would not let me do it frequently. Their orgasms would be much more explosive and longer period of having a high orgasmic feeling. I have gone from normal 6+ girth to nearly 8 girth with this method with the head proportionately larger than shaft. The head will be very hard for many hours. The next day or two, the whole penis will be much thicker than normal and a little longer in semi-hard condition and will be much heavier.
One not of caution: When using a much larger diameter tube, be very careful with your balls because thay can get sucked in also quickly with your penis and may make you faint from ball crushing pain.
I have seen specialty pumps for head and for balls. Just cruise internet for a large number of them.