Nexus is also known as 2C-B (4-Bromo-2,5-dimethoxyphenethylamine). It is suppose to be better than XTC for sex. Here is a little info on the drug:
2CB is highly dose sensitive. In its pure state the drug is active at 15 to 40 mg, depending on one's body size and sensitivity. At lower doses the drug is described as an energetic experience similar to ecstasy. At higher doses the experience is similar to that of LSD and ecstasy. People have reported heightened visual imagery, acute awareness of their bodies and increased sensitivity to smells, tastes and sexual stimulation. Effects seem to last from two to four hours, longer if taken on top of ecstasy.
Madhacker