По клику открыть меню

  $(function() { 
      $(".show__phones").on('click', function() { 
        $(".hide__phones").toggle(); 
      }); 
    });

.contacts__with__us { 
	display: flex; 
} 
.phones__main__info { 
	position: relative; 
} 
.phone { 
	margin-right: 5px; 
} 
.show__phones:hover { 
	cursor: pointer; 
} 
.hide__phones { 
  display: none; 
	position: absolute; 
	opacity: 1; 
	font-size: 14px; 
	text-align: center; 
	margin-top: 5px; 
	margin-left: 10px; 
} 
.hide__phones span:first-child { 
	margin-bottom: 5px; 
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
<div class="contacts__with__us"> 
					<div class="phones__block v-c"> 
						<div class="phones__main__info"> 
							<span class="phone">0(800) 215 350</span> 
              <a class="show__phones"><span>M</span></a> 
						</div> 
						 
						<div class="hide__phones"> 
							<span>0 (099) 215 350</span> 
							<span>0 (099) 215 350</span> 
						</div> 
					</div> 
</div>