Yup, I would use tape, too. Apply carefully and burnish well. If not happy with the ‘lay’, pull it up and re-lay it. May take several tries. Once the lay is good, burnish the deepest part of the groove first, then work your way up the sides.
Good tape is a must, Tamiya etc. no household painters tape. BMF is an alternative masking medium for irregular surfaces. Be aware that liquid masks can stain some non-glossy surfaces. If considering a putty for masking, such as the blue tac mentioned above, another option is silly putty, which can be quite versatile also.