the manga started releasing one year before the anime aired. Going by the constant pace of a chapter every 2-3 weeks, the manga will never catch up to the anime, especially after seaason 2 airs. Even then, the Light Novel will have more content unadapted by even the anime.
I would reccomend the LNs if you have a choice, just because there is interesting stuff that was cut and other than the first episode the animation is not that great.
"Indirect kiss" with a plastic cup feels forced... You'd need to intentionally put your lips on the exact same place on the rim. It's not a bottle or a can with a small opening.