上头 (shàngtou) as a position/direction word is the standard HSK7 meaning. But note:
上头 (shàngtóu) with a second tone on
头 has exploded as internet slang meaning 'to get a rush/buzz' - originally from the feeling of alcohol hitting your head, now used for anything exciting or addicting:
这首歌太上头了！ (This song is SO addicting!)
