The Greek men who exercised in the gymnasion were naked. Athletes were known for the beauty of their body. Therefore it could happen that spectators or fellow-athletes felt excitement when seeing a beautiful sportsman. Some athletes tied up their foreskin (‘infibulation’) as a precaution against an erection in public. Several athletes were famous for their great self-control with regard to sex.
All the athletes and spectators in the gymnasion were men. The Greeks were not very positive about homosexuality as such, but many made exception for the relation between an older man and a boy. Such relations were no disgrace. On the contrary, according to Plato it was the most noble form of love. Most Romans were far more recitent about it and considered the Greek behaviour immoral.
There were some rules for this Greek form of love, called pederasty. The boy (eromenos) was between 12 and 18 years old, already showing signs of puberty, but not yet fully grown, and had a passive role in the relationship. The man (erastes) was an adult and set himself up as the boy’s mentor. He asked the father of the boy for permission and tried to seduce the boy by giving him presents, e.g. a hare as a pet. In this context of courting belong the ‘kalos’-inscriptions on vases. These vases have a picture of a pretty boy with the inscription ‘xxx is beautiful (kalos)’.
Pederastic scenes on vases are often situated in the gymnasion. On the wall are then hanging a strigil, a sponge or an oil flask, the typical attributes of sportsmen. But this does not mean that gymnasia were places of obscene behaviour. Nudity and bodily contact were no permission for indiscrete sex.