1boy, 3girls, 3koma, 92m, ahoge, arm_behind_back, bare_shoulders, beach, bikini, black-framed_eyewear, black_hair, breasts, brown_eyes, cleavage, comic, covered_nipples, crop_top, crop_top_overhang, dateko, empty_eyes, glasses, holding, holding_innertube, innertube, kakita_(92m), kinshi_no_ane, large_breasts, looking_at_another, medium_breasts, multiple_girls, navel, ocean, open_mouth, original, otouto_(92m), outdoors, pink-framed_eyewear, ponytail, red_hair, see-through_silhouette, sky, sweatdrop, swimsuit, yellow_bikini