I'll follow Xorkoth's frequency and necro this thread ~4 years later
I primarily do psychoactive substances with my SOs so I've had sex on pretty much everything I tried - and I tried many things.
Although the thread is focused on psychedelics (which I'm defining as non-deliriant hallucinogens here) and dissos, I must make the honorable mention that GBL and stims/entactogens probably are the best enhancers of sex. These reliably make me horny, and make sex a lot more pleasurable as well. Entactogens also add such an interpersonal connection to the sex. Those who want to use peni in sex would benefit from some PDE5 inhibitors with these.
Dissos aren't the best for sex. I seldom feel the sex drive on more physical dissos (like O' PCE) but more manic and head high dissos (like 3-MeO-PCE, 3-MeO-PCP) work OK. Ultimately though, I don't find them very sex-enhancing, e.g. irrelevant thoughts visit my mind more often, I get more interested in what's in my mind than my partner, physical sensations are dimmed, and physical actions feel like a lot more work. Some of my female partners have had more libido than I did on dissos, so I've had sex on almost all dissos I tried, but without psychedelics (or entactogens) mixed in, I didn't find them noteworthy experiences. Note that depending on the dose or which part of the experience you're in (e.g. holing, or close to the peak), it may be plain impossible to consider or have sex on dissos.
Psychedelics, on the other hand, can be very interesting. I have so many memories of psychedelic sex etched in my mind. Few psychedelics are known to be very pro-sexual, such as 5-MeO-MiPT and 2C-B. They amplify and change physical sensations, visuals enrich the experience, and provide euphoria that culminates in a very intense orgasm (or multiple of them!). In general psychedelics can also deepen the connection between you and your partner, and make the sex feel like a mythical experience of reuniting with your lost half. But then, sometimes, it doesn't work that well, and you don't feel the connection or the desire and in such cases, it's almost impossible to even initiate it, let alone go through with it. I generally find phenethylamines (e.g. 2Cs) to be more tactile than tryptamines, and generally more social psychedelics (e.g. 4-AcO-MET) increase the chance of interpersonal engagement that may lead to play, compared to introspective ones (e.g. 4-AcO-DMT).
Disso sex can be more interesting with some psychedelics thrown into it. Moxy is my favorite psychedelic to mix with dissos and in many times, make the experience sexually inviting. E.g. Moxy mixed into MXE used to create these disembodied orgasmic waves (RIP MXE

), and make the connection feel very spiritual; or moxy with 3-MeO-PCP gave me electric tension in my muscles that I felt like I had to discharge by having intense sex. But then, some dissos, like MXP, can't ever become sexual, whatever you want add to them
Feel free to DM me with specific questions. I suck at periodically checking BL and regularly lose track of responding to discussions within threads. I'll list out dissos and psychedelics under the influence of which I had sex below, roughly in the order of preference for sex:
Dissos: MXE >>> K > 3-MeO PCP > 3-MeO-PCE >> 3-HO-PCP >>> O'PCE >>>>>>>> MXP
Psychedelics: 5-MeO-MiPT > 2C-B >> DOC > AL-LAD, LSD/1P-LSD > 4-AcO-MET > 4-HO-EiPT >> 2C-E >>> Shrooms/4-AcO-DMT