The title of this poem is derived from the expression 'To sow your wild oats'. It was culturally accepted by men at the time, that before marriage, men would be allowed to indulge in many sexual relationships with many women. The reasoning behind this is that if a man is not able to sow his wild oats, he will become anxious during his married years and begin to cheat on his wife. This story is told by Larkin aged 40, when he is still unmarried, and in this poem, he looks back to is younger days when he was around 20 years old. The poem describes one of his relationships in which he failed miserably. 20 years on from this event, he still has photos from it, but not of the girl he had a relationship with, but of her prettier friend.
This prettier friend is immediately described as "A bosomy English rose". This hints at how extremely beautiful she is and how Larkin considers her at the height of beauty. Larkin calls her "beautiful" and that is what he defines her as in his mind. He also remembers her very precisely even after 20 years, "I believe/ I met beautiful twice" and the fact that he remembers her so precisely shows how strong an impression she made on him. He also thinks that no one ever had any woman as beautiful as her, "I doubt/ If ever one had like hers". It is suggested that she knew she was superior (looks wise) to him, " She was trying/ Both times (so I thought) not to laugh"; this shows how she perhaps found it comical that Larkin was trying to charm her. But perhaps, Larkin is just being paranoid here, and in fact she was just behaving normally.
We find out at the end of verse 1 that even though he was much more attracted to "beautiful" he chose her less attractive friend to go out with, "But it was the friend I took out". Perhaps, he was intimidated by "beautiful" and her looks; and her friend was someone he found easier to relate to "her friend … I could talk to". This suggests that he was at ease and felt more confident