he forced his tongue against the cloth in his mouth but it would not budge , and the only noises he could make through the material were low , guttural moans , emanating from deep in his throat , sounding like a poor parody of a ventriloquist 's act ; sounds more suggestive of a lovemaking couple than a trapped prisoner , and guaranteed to ensure the ramblers wide berth rather than persuade him to investigate the source of the commotion .