![1boy 1girl animated arms_up bouncing_breasts bow bowtie breasts brown_hair collared_shirt hair_ornament hairclip happy jitome jumping kneehighs long_hair looking_at_another looking_at_viewer lowres nakamura_tarou onio purple_hair school_uniform shirt shoes short_hair skirt tachibana_yukino_(yuki_to_sumi) thigh_gap ugoira uwabaki very_long_hair white_shirt yuki_to_sumi rating:s score:4 1boy 1girl animated arms_up bouncing_breasts bow bowtie breasts brown_hair collared_shirt hair_ornament hairclip happy jitome jumping kneehighs long_hair looking_at_another looking_at_viewer lowres nakamura_tarou onio purple_hair school_uniform shirt shoes short_hair skirt tachibana_yukino_(yuki_to_sumi) thigh_gap ugoira uwabaki very_long_hair white_shirt yuki_to_sumi](/cdn_image/preview/30/ef/30ef45099b8cfb2409a54a6dd7375d2e.jpg)
Refers to breasts in motion, often as part of a .gif or flash animation. If it is not an animation, something like a motion blur or movement lines must be present to convey a sense of movement.
If one breast is up and the other is down, add the unaligned breasts tag as well.
Example: post #694780.
This tag implicates breasts (learn more).