Where is the riskiest place, public or otherwise, where you have masturbated or engaged in sex?

In the women's room of a crowded bar in St. Thomas. Ladies waiting in line were unimpressed. Her date was also not that excited when he eventually figured it out.

Same girl tried to get me to fuck her in the stairwell of a Miami Beach parking garage while we could hear people walking down towards us, I still regret telling her no.

Separately I fucked this girl from New Zealand multiple nights while we shared a room with several friends in a youth hostel. Taught me to have exceedingly quiet orgasms.