Well, according to this link, sacredsites.com/europe/england/cerne_giant.html.
If you take a sightline/alignment on May Day you should see the sun coming up;
to quote; “a sightline taken up the giant’s penis on May Day points directly at the sun as it rises over the crest of the hill”
So to verify this fact if anyone is around at dawn on May Day next year – please check..