There's Avebury plus lots of other semi-abandoned "stone circles" that you can headbut to your hearth's content.
Well if it is a dream, and money is no object, offer $1 million "donation" to the English heritage trust; then I am sure they will allow you to stroke the dolmens.
Else you can always hire mercenary commandos, neutralise the guards, and get intimate with the megaliths...
A simpler "solution" though would be to do a dodge and run during your inner tour and quickly caress a stone before spending the next few hours being questioned by the police and paying a fine....
A word of caution, as Stonehenge is highly mediatised, surrounded by wild theories, and shrouded by fantasy, and since it has been a lifelong dream for you... you might be quite underwhelmed by the reality of it.
For me, while being quite unimpressed by the henge itself, I found that the crows perched on the stones brought a sacred timeless dimension to the place.