how do i tell my friend she stinks?

i know this girl who’s in a lot of my classes and she usual sits relatively far from me. today for a group project she got closer to me and i got a whiff of this scent. the odor was so putrid i nearly gagged. it smelled like someone had dropped a log in their pants. anywhere i went with her had it. i tried to get away from her but she would not get the hint. it was beyond an uhealthy smell. you would think this girl lets it crust, no wipes. genuinely holding back the urge to tell her how to properly shower, or atleast turn on the water. how do i drop hints? i seriously cannot take it anymore her scent is nauseating.