x1=t1 is boxer shorts/boxer briefs/briefs/jockstrap (male genital underwear), serving purpose x2=t3
Male genitalia/crotch/penis-covering type of underwear. Needn't be worn by male/man/boy but garment need be made for male genitalia/pubic region in some manner (see fetpibyta'u/pibyta'u for female/non-defined counterpart). Cf. nerta'u, taxfrbikini, tatyta'u.