trigger updateDescClosedWon on Opportunity (after insert,after update) {

for ( Opportunity opp : Trigger.new ) {

    List <OpportunityContactRole> OppCR = [SELECT ContactID FROM OpportunityContactRole WHERE OpportunityID = :opp.Id];
    for (OpportunityContactRole currentContact : OppCr) {
        if ( opp.StageName == 'Closed Won' ) {

        List < Opportunity > oppList =  [SELECT Id, Name FROM Opportunity WHERE Id IN
        (SELECT OpportunityId FROM OpportunityContactRole WHERE ContactId =: currentContact.Id)];

        Contact newCount = [SELECT COUNT(Id) From Contact Where Id IN (SELECT ContactId FROM OpportunityContactRole)];
        }

}