Step 1: Put Grapefruit juice, Tequila, and Syrup into a martini shaker.
Step 2: Squeeze lime juice into the shaker.
Step 3: Press Orange Slice to the side of the glass.
Step 4: Fill the glass with ice.
Step 5: Shake martini shaker vigorously.
Step 6: Pour over the glass with ice.
Step 7: Garnish with basil.