To work with the rainbow in magic is not much different as either using colour magic, or the magic of other natural phenomena such as the Sun and Moon. Rainbow energy can be raised by the homemade rainbow methods above, and then channeled into the working. Nevertheless, here are some ideas on how to use rainbows in magic.
Charging: Charging your tools, amulets, jewellery, journals, plushies, decks, and whatever else you can think of with rainbow energy. This can be done by placing it in rainbow light, charging them when there is a rainbow, or on a charging plate. You can also first cleanse your tools or items in the rain, before charging them with rainbow energy.
Candles: Candle magic using seven candles in the individual colours, or using rainbow coloured candles. There are also drip candles, which are white on the outside and drip in rainbow colours as they burn. These are great for revealing magics, where the "true colours" are revealed as the candle burns down
Poppet magic: Poppets are often made from fabric, yarn, wheat, or clay, the last of which can be coloured. Making a poppet of rainbow fabric or draping a rainbow across the poppet can be used to bring rainbow energy into someone's life, or bring joy, wonder, and happiness.
Sachets or envelopes: Making sachets or envelopes in rainbow colours to make talismans, or put photos and petitions in them to charge with rainbow magic.
Rainbow water: Charging water while there is a rainbow, in the same way you would make moon water. Another way to make rainbow water is to place a bottle or glass of water on a charging plate, letting it soak up those good rainbow vibes. Another way is to divide your water up into seven, and use food colouring to colour it. Drink those colours!
Clothes: Bring some rainbow magic into your life by wearing rainbow clothing, jewellery, or accessories.
Meditation: Use meditation to connect with the magic of the rainbow. Sit in rainbow light, or drape a rainbow scarf or piece of fabric around you. Meditate while there is an actual rainbow outside. You can also try and find the end of the rainbow in meditation. You can meditate on the rainbow as a whole, or on the individual colours. For example meditate on one colour every day and see what this colour brings you. Or do a breathing meditation where with each inhale, you inhale a different colour of light.
Body: Makeup and face paint are another way to practice rainbow magic. There are some really cool rainbow makeup looks out there (like I wore to my wedding!), or you can use facepaint to draw sigils, symbols, or just a whole rainbow on you. If you want it to be more permanent, there are so many beautiful rainbow tattoo designs out there. Use this to bring in rainbow energy in general, or focus it on specific spots for some extra healing and oomph. Nailpolish is also a great way to carry a bit of rainbow with you.
Kitchen Witchery: Rainbow foods. Just, rainbow foods. I have a pinterest board. They are so cool and fun.
Crystals: Above I mentioned some crystals which look like captured rainbows. Use them in magic, or use seven different stones for the seven colours of the rainbow. My favourite set is garnet, carnelian, citrine, aventurine, turquoise, sodalite, and amethyst.
Fabric Arts: weaving with colours, braiding seven colours together, knot magic with different beads knotted in the yarn, crocheting with rainbow yarn, rainbow friendship bracelets, there are a lot of ideas here.
Time: Not something I personally use, but there are seven days in the week, and seven colours in the rainbow. These facts can be combined to make magic.
Visionboards: Making visionboards are a great way to tap into rainbow magic and bring it into your life, especially if you also incorporate the words of the associations you want to use.
Inner Child work: Ever notice how so many toys are multicoloured and fun. How crayons and pencils come in the colours of the rainbow with a few added ones. Practice inner child work by playing. Just play, let out you inner gremlin and create or play without fear or shame.
Altar: Create an altar for your rainbow magic, rainbow entity, or just a "wonder altar" in general. Add things that bring that same burst of joyous wonder that you feel when you see a rainbow. Some ideas for your rainbow altar are rainbow candles, statues of rainbows (tip: Christmas ornaments!), pictures or art, unicorns, golden coins, pride flags, prisms, rainbow lights, rainbow roses (real or fake), crystals, art supplies, and bubble wands.
Music: Why are there so many songs about rainbows? (I had to) But Kermit was right, there are many songs about rainbows so why not make a playlist for your rainbow magic?
Sigils: Draw sigils with a rainbow pencil (remember those?), layer the different colours over one another, or draw pieces of the sigil in different sparkly pens to make them rainbow.
Galaxy Jars: These are jars filled with cotton balls, water, glitter, and food colouring. By packing the cotton tight these jars look like a galaxy. You can use one jar per colour, or make a layered jar with all the colours of the rainbow. I like to hide little pouches with herbs, sigils, and crystal chips in my galaxy jars to make them spell jars.
Natural dyes: Using dyes or inks made out of herbs, flowers, vegetables, plants, minerals and fruits can draw the energy of those materials into your rainbow magic as well.
Queer Magic: The rainbow has been inextricably linked to the queer community. Therefore rainbow energy can also be used in queer magic. for example in community protection spells, pride flag spell bottles (using Gilbert Bakers colour meanings), charming pronoun pins, and queer tarot spreads.
[Part of a Rainbowmancy series, masterpost here]