This item is made of soft silicon but it is cone shaped inwards although the rim fits flatly against the ends of both the Vacurect and Mojo pumps. The opening is well inside the edge of the pumps and so any engorgement of the penis starts a long way from the base of the penis. It could be cut back to overcome this to some extent but would leave the hole too large to act as a constriction ring and also risk sucking in a testicle. It's construction outside of the pump would, however, allow a constriction ring to be placed so it may be useable, although I didn't cut it back or try that approach.