tribulus can have pro-sexual and mood effects. however as noted it does not raise testosterone, this has been fairly well established clinically.
there may be a PARTIAL exception, in those experiencing some HPGA suppression from prolactin (as tribulus does have some dopaminergic activity). But this has not been established and is only theoretical.
you are of course in that case better off with proven dopaminergics like bromocriptine, selegiline, cabergoline, l-dopa, etc...