Green’s Dictionary of Slang

bugle n.²

1. the penis.

1839		Crim.-Con. Gaz. 12 Oct. 239/1: Miss Rich [was] protesting unutterable attachment to him; and urging his study on the bugle horn in addition to that of the flute.
1973		L. Shecter On the Pad 84: George Piccolo, ‘a guy with a tremendous bugle on him,’.

2. (Irish) an erection.

1991		R. Doyle Van (1998) 395: He could’ve given himself a bugle now, out here in the hall, just remembering what she was like.
2002		O’Byrne Files: Dublin Sl. Dict. 🌐 Bugle n. Erection.

In compounds

bugle boy (n.) [one blows/blow v.² (1c) a bugle/bugle n.² ]

(US gay) a passive male homosexual.

1965		Guild Dict. Homosexual Terms 6: bugle boy (n.): Refers to the person who permits someone to perform fellation upon him. This term has come into vogue with the sophisticated college set.
1972		(ref. to early 1960s) B. Rodgers Queens’ Vernacular 33: to suck a penis [...] play bugle boy (early ’60s, hetero college sl: ‘I let some fag play bugle boy, but I didn’t do one thing to help him come ... I’m not queer’).