There are two main things to take from this chapter;
1. Not only is Senpai letting himself take more risks that he wouldn't try to do earlier, but he also got Nagatoro all flustered in the process again.
2. Nagatoro noted that Senpai drinks that 5% orange juice all the time, while drinking the same beverage, stating she doesn't "usually drink this". She's unintentionally admitting that she pays so much attention to Senpai that she knows what kind of juice he always buys and also trying to get more familiar with what Senpai likes. That's sweet.
Also the indirect kiss trope is weird (maybe it's a Japanese thing like the nosebleed trope), but since they're both obviously inexperienced when it comes to romantic relationships, there's some leeway with them getting nervous over something silly like an ambiguous indirect kiss.