Ciao Maik,
I have been once before to Phuket but didn't go with any bg or alike coz I had already company... Nevertheless if your hotel isn't a girlfriendly you can always go to a massage parlour... I have heard Christines parlour is a good one and I think the prices are around 2000 baht. But I don't know for how long nor for how many rounds...
I have also heard that the place have about 100 girls or more. I read they have two types of services Massage + boom boom and boom boom only... What surprises me the most is that boom boom only is more costy then boom boom + massage....????.... I don't know anything about rules nor anything alike, I think the elders here could advice you more about it. However one thing I remember from what I read is to avoid taking a tuk tuk to the place coz the driver will demand commission...
Have fun!