You can shake the tassles, you can shake them into a paper bag and try to empty the pollen onto the silks, etc. If the silks are out, some pollen may already have been dispersed, look at the leaves for signs. If there's lots of pollen on the leaves, you can try to bend a leaf to the silk and try to wipe it onto the silks. Plus if you have the right wind direction, that helps too.

Remove a tassle from one plant and whack it on the silks of all others. The next day and the next day repeat.