Anything「difficult to forget one's entire life」must surely be GRIEVOUS, PAINFUL. Pleasurable masturbation by males is normally forgotten just a few moments afterwards. Perhaps when one is GRIEVED, PAINED then masturbation and the accompanying small dopamine rush is more likely to provide some SOLACE with the「deep feeling of prick in squeezing grip」(although, most folks have reported that neither being in grief nor feeling pain is required to begin masturbating every time).
　Also a possibility though is「begging mother with prick request」that might finally result in some GRIEF for all involved:
　「In Japan, it is not uncommon for mothers to sexually stimulate their children to soothe them…. There have been stories in the press of mother-son incest arising from the strong nature of this relationship in Japan and the important maternal role of ensuring the son succeeds at school. According to Hideo Tokuoka, 'When Americans think of incest, they think of fathers and daughters. In Japan one thinks of mothers and sons' due to the extensive media coverage of mother-son incest there.」
　　[　https://en.wikipedia.org/wiki/Incest 2012-08-21　]　
　Without a doubt, the Irish also have knowledge of their own to pass along in these trying times:「Masturbation will not spread coronavirus, especially if you wash your hands (and any sex toys) with soap and water for at least 20 seconds before and after.」Nonetheless and regrettably, unlike in dynastic China, it must be undertaken alone to truly be a preventative countermeasure but still achieve the desired result with some degree of safety.
　 　[　https://www.sexualwellbeing.ie/sexual-health/sex-and-coronavirus/ 2020-03-31　]　
　The Dutch, too have the same solution—it seems masturbation has become mainstream in the media the world over due to the coronavirus (it has always been 'the main stream' in reality, albeit covertly for most folks):
　「'Don't have sex with your partner if they have been isolated because of (suspected) coronavirus infection,' the RVIM says. 'Sex with yourself or with others at a distance is possible (think of telling erotic stories, masturbating together).'」
　　[　https://www.theguardian.com/world/2020/may/15/dutch-official-advice-to-single-people-find-a-sex-buddy-for-lockdown-coronavirus 2020-05-16　]　
　Needless to point out perhaps, but Chinese shamans from antiquity hit upon the same solution as a pandemic preventative countermeasure, honed for ultimate client satisfaction by utilizing naked females with no-longer-integrated feet as masturbatory sex buddies available for short-term rental with erotic visualization of live prepubescent female genitalia engaging in autoerotic stimulation herself, as a solution to the same problem facing us now, but in pre-Internet days.

Modern definitions (that generally disregard history) …excluding politically incorrect concepts and other meanings deemed offensive today; may list only pigeonholed definitions, euphemisms, or meaningless mnemonics)
Unihan extended: (simplified form of 懤) grieved, pained