A Tantric workshop is more like a sample (the same with a Tantric massage). Call it a Tantra Teaser.. If you are not sure whether Tantra is for you or not, go for a short one - even a one day introduction would do!
Useful sites for Tantric courses and workshops:
In Denmark - Copenhagen: Agama Yoga
In Thailand: Agama Yoga
In Estonia - Taliinn And Tartu
In Hungary - Budapest: Agama Yoga
In The Netherlands- Amsterdam: Agama Yoga