As in many of Tennessee Williams's plays, there is a homoerotic/homosexual subtext. We are led to believe, though it is never directly stated, that Skipper—Brick's best friend and former high school teammate—harbored romantic feelings for Brick and was a closeted gay man. Consider this in lieu of the following from Act One:
Margaret: But that fall you an' Skipper turned down wonderful offers of jobs in order to keep on bein' football heroes—pro-football heroes. You organized the Dixie Stars that fall, so you could keep on bein' team-mates for ever! But somethin' was not right with it!—Me included!—between you. Skipper began hittin' the bottle... you got a spinal injury—couldn't play the Thanksgivin' game in Chicago, watched it on TV from a traction bed in Toledo. I joined Skipper. The Dixie Stars lost because poor Skipper was drunk. We drank together that night all night in the bar of the Blackstone and when cold day was comin' up over the Lake an' we were comin' out drunk to take a dizzy look at it, I said, 'SKIPPER! STOP LOVIN' MY HUSBAND OR TELL HIM HE'S GOT TO LET YOU ADMIT IT TO HIM!'—one way or another! HE SLAPPED ME HARD ON THE MOUTH!—then turned and ran without stopping once, I am sure, all the way back into his room at the Blackstone....
When I came to his room that night, with a little scratch like a shy little mouse at his door, he made that pitiful, ineffectual little attempt to prove that what I had said wasn't true— [Brick strikes at her with crutch, a blow that shatters the gemlike lamp on the table.] In this way, I destroyed him, by telling him truth that he and his world which he was born and raised in, yours and his world, had told him could not be told?
The phrases "football heroes" and "teammates" act as code here. Sports are one of few contexts in which men are allowed to express affection for each other, are allowed to touch each other, and express admiration for one another. Brick and Skipper wanted to "keep on bein' team-mates" forever so that they would be allowed to demonstrate that love without being suspected of homosexuality.
Homosexuality is the "truth" that could not be spoken in Brick's and Skipper's world. "World" here has multiple connotations: the world of sports and athleticism, the South, and white masculinity. These are the worlds in which "[Skipper] was born and raised." Homosexuality was not discussed or acknowledged among people in Brick's and Skipper's world(s).
It becomes clear, through Maggie's recollection of an encounter with Skipper, that she was aware of his being in love with Brick. Brick's love for Skipper is not made as clear through the dialogue, however it is strongly suggested by the exposition in the play, in which Brick repeatedly "strikes" at Maggie with his crutch. By hurting her, he can get her to shut up and avoid reminding him of what he felt for Skipper, a feeling he numbs with alcohol. Before killing himself, Skipper, too, had become dependent on alcohol, as well as drugs, in an attempt to forget his feelings and to anesthetize himself. In this way, alcohol acts as a trope in the play. It symbolizes the need to avoid confronting feelings and needs that are socially unacceptable.
Maggie also admits that she and Skipper "made love to each other to dream it was [Brick]," in a desperate attempt for both to be closer to him. Maggie wanted to experience, through Skipper, the intimacy her marriage lacked; while Skipper wanted to experience, through Maggie, the physical desire he felt for Brick.
Other readings of the play have determined that Brick's drinking is a sign of his impotence. Maggie is clearly sexually frustrated because Brick will not sleep with her (a fact that is overtly stated by her sister-in-law, Mae); and Maggie, though not Brick, is mocked for not having children. There is a cruel irony in the fact that this woman, whom we are told is young and highly desirable, is unable to get her husband to go to bed with her. His lack of desire is another indication of Brick's homosexuality. He is unable to perform with Maggie because he is not really attracted to her.
Another reading considers the crutches (the word "crutch" is both literal and symbolic here) as Brick's inability to let go of the past, his dependency on the memory of Skipper and their past glories. They were "football heroes," a designation which bears romantic meaning. He cannot let go of this memory until he admits, during his conversation with Big Daddy, that he has been dishonest with himself about the nature of his relationship with Skipper. Once he is able to confront these feelings, he is able to make love to his wife.