What does Montag do to Mildred's friends and what is their reaction?
As the previous educator has commented, Montag engages Mildred's friends, Mrs Bowles and Mrs Phelps, in conversation and reads a poem to them. Whispering in his ear, Faber warns Montag not to read the poem, presumably because he is worried that the women will report him to the authorities for possessing a book. But Montag ignores Faber's request and reads the poem anyway, on the premise that he wants to "scare the hell" out of the women.
The poem Montag selects is significant: "Dover Beach" presents a world which was once filled with "faith" and love but is now a hotbed of uncertainty and ignorance. This represents Montag's intellectual awakening and, by reading it to the women, he hopes that it will resonate with the women in some way. The effect of the reading, however, is far more dramatic than he might have imagined: Mrs Phelps "sobs bitterly" after hearing the poem, arguably because she recognises the emptiness presented in "Dover Beach" as being reminiscent of her own world. In contrast, Mildred and Mrs Bowles are angry with Montag and attack him for causing so much distress. They leave and vow to never return to the house, prompting Mildred to hide some of Montag's books in the garden out of fear that they might report her husband.
In the book, what Guy Montag does is a couple of things. First, he tries to engage the women in conversation about things like the war and their families. This is something that is apparently just not done in their society. It is unwelcome because it is trying to get them to think and feel.
Second, he tries to read poetry to them. In the case of the conversation, they react by being very uncomfortable and trying to break it off. They fidget and look around nervously. When he reads to them, they completely freak out and want to leave. They talk about how horrible the poetry is and how horrible he is.