Break your team up into 2 or 3 teams. If you do 2 teams you’ll need 8 or 9 on a team with a player for each defensive position. If you only have 8 on a team you can eliminate either the pitcher, catcher, or one outfielder based on what is a priority for your team that day. If you only have 12-15 players on your team break it up into 3 teams of 4-5. Then place two of the teams on defense and one team hitting fungoes. No matter what, have the teams and batting orders pre-made before practice. This will eliminate unnecessary downtime during practice.
The bat's form has become more refined over time. In the mid-19th century, baseball batters were known to shape or whittle their own bats by hand. This allowed there to be a wide variety in shape, size, and weight. For example, there were flat bats, round bats, short bats, and fat bats. Earlier bats were known to be much heavier and larger than today's regulated ones. During the 19th century, many shapes were experimented with, as well as handle designs. Today, bats are much more uniform in design.
This is the drill we ran all through high school. It is the most time effective and skill intensive way to warm up a team, but your boys must be able to play catch! Fungo-ers stand in the "fungoe circles" that any good field has (and if it doesn't, you know where they're supposed to be - just outside of the home-plate dirt circle, towards the dugouts). The catch to this method is this - you have two first basemen, allowing both sides of the infield to throw across. Herein lies the only danger - one of the firstbasemen has a lengthy throw back to a shagger, so caution must be excersized (a catcher with a good head on his shoulders really helps).
They can either be wood or aluminum. I encourage you to use a wood one. If not, I will make fun of you like I do my good friend Bill Booker at LaSalle-Peru H.S. for using his aluminum one. If you choose the wood fungo, I would recommend taping the barrel. If you hit a good number of fungoes, the tape will increase the durability of the bat. I took the tape off of one once. The barrell was like sawdust, but I re-taped it and it was ready to go. One season, I figured it out, between the high school, American Legion, an junior high seasons I had hit over 10,000 fungoes. Tape it up!