kai (charcoal), kai (pixiv463508), hatsune miku, kagamine len, kagamine rin, vocaloid, striped, bad id, bad pixiv id, 2girls, 3boys, aged down, anklet, aqua eyes, barefoot, beach, bench, bikini, blonde hair, blue jammers, blue male swimwear, blue swim trunks, child, drink, feet, goggles, goggles on head, headphones, jammers, jewelry, long hair, male swimwear, multiple boys, multiple girls, multiple persona, music, shirt tan, singing, sitting, sunglasses, swim trunks, swimsuit, tan, tanline, time paradox, topless male, twintails, very long hair