Orgasm suppression (formally known as anorgasmia) can be described as a difficulty or complete inability to achieve orgasm despite adequate sexual stimulation. 
This effect commonly occurs on opioids and dissociatives which have been reported to decrease one's ability to feel sexual pleasure, which may be attributed to their tactile suppressing effects or through some other biological mechanism. It is also a well-known side effect of selective serotonin reuptake inhibitors (SSRIs).  It may also be a result of the effect known as difficulty urinating which can occur on certain stimulants and entactogens. This effect has been reported to occur alongside a decrease in the strength of one's kegel muscles, which may account for the inability to achieve ejaculation and orgasm within males.
- Brindley, G. S., & Gillan, P. A. T. R. I. C. I. A. (1982). Men and women who do not have orgasms. The British Journal of Psychiatry, 140(4), 351-356. | https://doi.org/10.1192/bjp.140.4.351
- Ashton, A. K., Hamer, R., & Rosen, R. C. (1997). Serotonin reuptake inhibitor-induced sexual dysfunction and its treatment: a large-scale retrospective study of 596 psychiatric outpatients. Journal of sex & marital therapy, 23(3), 165-175. | http://dx.doi.org/10.1080/00926239708403922