I have two kids with this same issue. We tried heaps of different brands and the cancer council one was their choice (smelt the least, felt the least oily and soaked in the fastest). We tell them no sun cream means you can't go outside and eventually they usually give in begrudgingly. Perhaps desensitising them a little first might work. I have two kids that were horrible with socks and shoes. We were told to hold their foot in your hand and use pressure firmly holding for about 10 seconds. Perhaps if you did that on their arm and then put the cream on their arm it might work? Or ask an occupational therapist for some ideas? Skin brushing might even be useful ask its great for desensitising for clothing, etc. Good luck - I still dread summer for sun cream - almost as much as winter and jumpers!