Mix together dry ingredients. Cut in butter and mayonnaise until pebbly.
Slowly mix milk until everything follows, as you stir.
Flour board, dump out carefully, and knead the dough until you have folded three to five times. Keep it minimal. Do not overwork the dough, or it will be tough. Do not under work the dough, or it will not rise well. Cut into any shape you desire. You're not limited to round biscuit cutters! There are thousands of cookie cutters which make nice novelty biscuits!
Place cut biscuits on parchment-lined baking sheet and bake for 10-12 minutes or until golden on top. I roll mine thin on purpose. The photo above is not an indication of a weak rise. ;).